The port is free but server doesn't start

Hi,

In last weeks I have been facing this problem several time. First it started with neo4j 4.1.3. that during change of database I had some issues. Then I tried to have a fresh database, but I couldn't start the server even though the port was free. later I downloaded neo4j 4.2.1 and it worked. But after couple of days during loading new data I faced the same problem and it doesn't start anymore. I get this error:

Directories in use:
  home:         /export/work/neo4j/neo4j-community-4.2.1
  config:       /export/work/neo4j/neo4j-community-4.2.1/conf
  logs:         /export/work/neo4j/neo4j-community-4.2.1/logs
  plugins:      /export/work/neo4j/neo4j-community-4.2.1/plugins
  import:       /export/work/neo4j/neo4j-community-4.2.1/import
  data:         /export/work/neo4j/neo4j-community-4.2.1/data
  certificates: /export/work/neo4j/neo4j-community-4.2.1/certificates
  run:          /export/work/neo4j/neo4j-community-4.2.1/run
Starting Neo4j.
WARNING: Max 1024 open files allowed, minimum of 40000 recommended. See the Neo4j manual.
2020-12-10 16:29:24.866+0000 INFO  Starting...
2020-12-10 16:29:26.423+0000 INFO  ======== Neo4j 4.2.1 ========
WARNING: sun.reflect.Reflection.getCallerClass is not supported. This will impact performance.
2020-12-10 16:29:39.142+0000 ERROR Failed to start Neo4j on dbms.connector.http.listen_address, a socket address. If missing port or hostname it is acquired from dbms.default_listen_address.
java.lang.RuntimeException: Error starting Neo4j database server at /export/work/neo4j/neo4j-community-4.2.1/data/databases
        at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:207) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.build(DatabaseManagementServiceFactory.java:163) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.server.CommunityBootstrapper.createNeo(CommunityBootstrapper.java:36) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.server.NeoBootstrapper.start(NeoBootstrapper.java:134) [neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.server.NeoBootstrapper.start(NeoBootstrapper.java:90) [neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.server.CommunityEntryPoint.main(CommunityEntryPoint.java:35) [neo4j-4.2.1.jar:4.2.1]
Caused by: org.neo4j.kernel.lifecycle.LifecycleException: Component 'org.neo4j.dbms.database.DefaultSystemGraphInitializer@5f14761c' was successfully initialized, but failed to start. Please see the attached cause exception "User limit of inotify watches reached".
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:463) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:198) ~[neo4j-4.2.1.jar:4.2.1]
        ... 5 more
Caused by: java.lang.IllegalStateException: Failed to initialize system graph component: This database is shutdown.
        at org.neo4j.dbms.database.SystemGraphComponents.initializeSystemGraph(SystemGraphComponents.java:102) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.DefaultSystemGraphInitializer.initializeSystemGraph(DefaultSystemGraphInitializer.java:41) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.SystemGraphInitializer.start(SystemGraphInitializer.java:29) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:198) ~[neo4j-4.2.1.jar:4.2.1]
        ... 5 more
Caused by: org.neo4j.graphdb.DatabaseShutdownException: This database is shutdown.
        at org.neo4j.kernel.availability.DatabaseAvailabilityGuard.assertDatabaseAvailable(DatabaseAvailabilityGuard.java:172) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginKernelTransaction(GraphDatabaseFacade.java:197) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransactionInternal(GraphDatabaseFacade.java:176) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:122) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:116) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:104) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTx(GraphDatabaseFacade.java:99) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractSystemGraphComponent.detect(AbstractSystemGraphComponent.java:118) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractSystemGraphComponent.initializeSystemGraph(AbstractSystemGraphComponent.java:93) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.SystemGraphComponents.initializeSystemGraph(SystemGraphComponents.java:92) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.DefaultSystemGraphInitializer.initializeSystemGraph(DefaultSystemGraphInitializer.java:41) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.SystemGraphInitializer.start(SystemGraphInitializer.java:29) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:198) ~[neo4j-4.2.1.jar:4.2.1]
        ... 5 more
        Suppressed: org.neo4j.graphdb.DatabaseShutdownException: This database is shutdown.
                at org.neo4j.kernel.availability.DatabaseAvailabilityGuard.assertDatabaseAvailable(DatabaseAvailabilityGuard.java:172) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginKernelTransaction(GraphDatabaseFacade.java:197) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransactionInternal(GraphDatabaseFacade.java:176) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:122) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:116) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:104) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTx(GraphDatabaseFacade.java:99) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractSystemGraphComponent.detect(AbstractSystemGraphComponent.java:118) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractSystemGraphComponent.initializeSystemGraph(AbstractSystemGraphComponent.java:93) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.SystemGraphComponents.initializeSystemGraph(SystemGraphComponents.java:92) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultSystemGraphInitializer.initializeSystemGraph(DefaultSystemGraphInitializer.java:41) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.SystemGraphInitializer.start(SystemGraphInitializer.java:29) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:198) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.build(DatabaseManagementServiceFactory.java:163) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.CommunityBootstrapper.createNeo(CommunityBootstrapper.java:36) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.NeoBootstrapper.start(NeoBootstrapper.java:134) [neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.NeoBootstrapper.start(NeoBootstrapper.java:90) [neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.CommunityEntryPoint.main(CommunityEntryPoint.java:35) [neo4j-4.2.1.jar:4.2.1]
        Caused by: org.neo4j.kernel.lifecycle.LifecycleException: Component 'org.neo4j.io.fs.watcher.DatabaseLayoutWatcher@2c719bd4' was successfully initialized, but failed to start. Please see the attached cause exception "User limit of inotify watches reached".
                at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:463) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.database.Database.start(Database.java:511) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startDatabase(AbstractDatabaseManager.java:187) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:152) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:36) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.forEachDatabase(AbstractDatabaseManager.java:165) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startAllDatabases(AbstractDatabaseManager.java:112) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.start(AbstractDatabaseManager.java:106) ~[neo4j-4.2.1.jar:4.2.1]
                ... 8 more
        Caused by: java.io.UncheckedIOException: java.io.IOException: User limit of inotify watches reached
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.watchFile(DatabaseLayoutWatcher.java:122) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.startWatching(DatabaseLayoutWatcher.java:110) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.watchDirectories(DatabaseLayoutWatcher.java:85) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.start(DatabaseLayoutWatcher.java:65) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.database.Database.start(Database.java:511) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startDatabase(AbstractDatabaseManager.java:187) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:152) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:36) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.forEachDatabase(AbstractDatabaseManager.java:165) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startAllDatabases(AbstractDatabaseManager.java:112) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.start(AbstractDatabaseManager.java:106) ~[neo4j-4.2.1.jar:4.2.1]
                ... 8 more
        Caused by: java.io.IOException: User limit of inotify watches reached
                at sun.nio.fs.LinuxWatchService$Poller.implRegister(LinuxWatchService.java:266) ~[?:?]
                at sun.nio.fs.AbstractPoller.processRequests(AbstractPoller.java:265) ~[?:?]
                at sun.nio.fs.LinuxWatchService$Poller.run(LinuxWatchService.java:366) ~[?:?]
                at java.lang.Thread.run(Thread.java:834) ~[?:?]
        Suppressed: org.neo4j.graphdb.DatabaseShutdownException: This database is shutdown.
                at org.neo4j.kernel.availability.DatabaseAvailabilityGuard.assertDatabaseAvailable(DatabaseAvailabilityGuard.java:172) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginKernelTransaction(GraphDatabaseFacade.java:197) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransactionInternal(GraphDatabaseFacade.java:176) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:122) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:116) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTransaction(GraphDatabaseFacade.java:104) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.beginTx(GraphDatabaseFacade.java:99) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractSystemGraphComponent.detect(AbstractSystemGraphComponent.java:118) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractSystemGraphComponent.initializeSystemGraph(AbstractSystemGraphComponent.java:93) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.SystemGraphComponents.initializeSystemGraph(SystemGraphComponents.java:92) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultSystemGraphInitializer.initializeSystemGraph(DefaultSystemGraphInitializer.java:41) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.SystemGraphInitializer.start(SystemGraphInitializer.java:29) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:198) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.build(DatabaseManagementServiceFactory.java:163) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.CommunityBootstrapper.createNeo(CommunityBootstrapper.java:36) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.NeoBootstrapper.start(NeoBootstrapper.java:134) [neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.NeoBootstrapper.start(NeoBootstrapper.java:90) [neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.server.CommunityEntryPoint.main(CommunityEntryPoint.java:35) [neo4j-4.2.1.jar:4.2.1]
        Caused by: org.neo4j.kernel.lifecycle.LifecycleException: Component 'org.neo4j.io.fs.watcher.DatabaseLayoutWatcher@2c719bd4' was successfully initialized, but failed to start. Please see the attached cause exception "User limit of inotify watches reached".
                at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:463) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.database.Database.start(Database.java:511) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startDatabase(AbstractDatabaseManager.java:187) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:152) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:36) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.forEachDatabase(AbstractDatabaseManager.java:165) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startAllDatabases(AbstractDatabaseManager.java:112) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.start(AbstractDatabaseManager.java:106) ~[neo4j-4.2.1.jar:4.2.1]
                ... 8 more
        Caused by: java.io.UncheckedIOException: java.io.IOException: User limit of inotify watches reached
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.watchFile(DatabaseLayoutWatcher.java:122) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.startWatching(DatabaseLayoutWatcher.java:110) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.watchDirectories(DatabaseLayoutWatcher.java:85) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.start(DatabaseLayoutWatcher.java:65) ~[neo4j-layout-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
                at org.neo4j.kernel.database.Database.start(Database.java:511) ~[neo4j-kernel-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startDatabase(AbstractDatabaseManager.java:187) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:152) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:36) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.forEachDatabase(AbstractDatabaseManager.java:165) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.startAllDatabases(AbstractDatabaseManager.java:112) ~[neo4j-4.2.1.jar:4.2.1]
                at org.neo4j.dbms.database.AbstractDatabaseManager.start(AbstractDatabaseManager.java:106) ~[neo4j-4.2.1.jar:4.2.1]
                ... 8 more
        Caused by: java.io.IOException: User limit of inotify watches reached
                at sun.nio.fs.LinuxWatchService$Poller.implRegister(LinuxWatchService.java:266) ~[?:?]
                at sun.nio.fs.AbstractPoller.processRequests(AbstractPoller.java:265) ~[?:?]
                at sun.nio.fs.LinuxWatchService$Poller.run(LinuxWatchService.java:366) ~[?:?]
                at java.lang.Thread.run(Thread.java:834) ~[?:?]
Caused by: org.neo4j.kernel.lifecycle.LifecycleException: Component 'org.neo4j.io.fs.watcher.DatabaseLayoutWatcher@2c719bd4' was successfully initialized, but failed to start. Please see the attached cause exception "User limit of inotify watches reached".
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:463) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.database.Database.start(Database.java:511) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.startDatabase(AbstractDatabaseManager.java:187) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:152) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:36) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.forEachDatabase(AbstractDatabaseManager.java:165) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.startAllDatabases(AbstractDatabaseManager.java:112) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.start(AbstractDatabaseManager.java:106) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:198) ~[neo4j-4.2.1.jar:4.2.1]
        ... 5 more
Caused by: java.io.UncheckedIOException: java.io.IOException: User limit of inotify watches reached
        at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.watchFile(DatabaseLayoutWatcher.java:122) ~[neo4j-layout-4.2.1.jar:4.2.1]
        at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.startWatching(DatabaseLayoutWatcher.java:110) ~[neo4j-layout-4.2.1.jar:4.2.1]
        at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.watchDirectories(DatabaseLayoutWatcher.java:85) ~[neo4j-layout-4.2.1.jar:4.2.1]
        at org.neo4j.io.fs.watcher.DatabaseLayoutWatcher.start(DatabaseLayoutWatcher.java:65) ~[neo4j-layout-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.database.Database.start(Database.java:511) ~[neo4j-kernel-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.startDatabase(AbstractDatabaseManager.java:187) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:152) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.DefaultDatabaseManager.startDatabase(DefaultDatabaseManager.java:36) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.forEachDatabase(AbstractDatabaseManager.java:165) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.startAllDatabases(AbstractDatabaseManager.java:112) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.dbms.database.AbstractDatabaseManager.start(AbstractDatabaseManager.java:106) ~[neo4j-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:442) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:110) ~[neo4j-common-4.2.1.jar:4.2.1]
        at org.neo4j.graphdb.facade.DatabaseManagementServiceFactory.startDatabaseServer(DatabaseManagementServiceFactory.java:198) ~[neo4j-4.2.1.jar:4.2.1]
        ... 5 more
Caused by: java.io.IOException: User limit of inotify watches reached
        at sun.nio.fs.LinuxWatchService$Poller.implRegister(LinuxWatchService.java:266) ~[?:?]
        at sun.nio.fs.AbstractPoller.processRequests(AbstractPoller.java:265) ~[?:?]
        at sun.nio.fs.LinuxWatchService$Poller.run(LinuxWatchService.java:366) ~[?:?]
        at java.lang.Thread.run(Thread.java:834) ~[?:?]
2020-12-10 16:29:39.145+0000 INFO  Neo4j Server shutdown initiated by request
2020-12-10 16:29:39.145+0000 INFO  Stopped.

to me it seems even though I have removed the database or java it is still somewhere locked, but don't know where. If I download neo4j 3 it is working but not the 4.

i have same issue when i upgrade 4.5 to 5.4