I am facing a problem for a while and I still dont know whats wrong. Desktop-Version: 1.4.8
I can`t start any DBMS, no matter which version it is. Once it worked perfectly, but than I got the massage "DMBS failed to start: DBMS process terminated, see logs... "
Sorry to hear about that, that's frustrating. There isn't a clear indication from that log file snippet about what might be wrong. The ports refusing connection could either be because the process has failed, or because something is blocking the port access.
What OS are you running on? And what user/admin permissions do you have? Can you think of anything else that might've changed on your system?
Also, could you attach your neo4j.log? In Desktop, select the DBMS, then click on the three-dots menu, then choose "Logs..." to see a window which shows all the logs. Click on the neo4j.log
The ClassNotFoundException looks like the reason for the script failing. When the script runs, it creates a "classpath" to look for Neo4j components. That is failing for some reason, either because the location is wrong or because of a permission problem.
You mention this was previously working, and that now no DBMS will launch. Does it also fail for newly created DBMSes?
Yes it does. I will get the same error for a new created DBMS, no matter which version (4.2.x or 4.3.x)
My Neo4J_HOME (user & system)-variable is on ...\Local\Neo4j\Relate\Data\dbmss\dbms-1878d38c-984a-43e4-af4f-cc13f8b41102 , which is my main dbms, I am using.
Is this right or does this no matter?
We had exactly the same issue for one developer, and the fun thing is that it started quite suddenly. The DB worked perfectly for months, and then it suddenly stopped working when he upgraded his DB version from 4.2.x or 4.3.x to 4.3.6.
We tried uninstall, delete everything, reinstall; compared class files between installations etc. No luck.
In the end @abk's comment about neo4j-start.ps1 setting the classpath brought us to the right idea. The developer had once installed Neo4j 3.5 using the Windows package manager "chocolatey" (we didn't have any experience with Neo4j Desktop back then). After we noticed this only installs 3.5 (and we wanted to start with 4) we switched to Neo4j Desktop.
Unfortunately, the chocolatey package globally sets NEO4J_HOME environment variable to its own installation (c:\tools\neo4j-community or something). Removing that environment variable and removing leftovers from the chocolatey package fixed the problem, the DB started again.
@dionisios95 if you still have the problem, I suggest you check the NEO4J_HOME variable or delete it. My installation doesn't require it to be set in Windows.
My proposal for Neo4j would be to do more logging inside the startup scripts. We could have found this issue a lot sooner if the startup scripts log their actions. The error message "class not found" is not really helpful if I don't know what the classpath is.