Pydev keeps forgetting interpreter settings, "unknown encoding: idna" keeps showing up in logs

Every time I restart Eclipse, none of my python3 files open because eclipse says they use the wrong interpreter settings. When I go resolve the interpreter settings I see that none of the configuration I made is there, and I have to set a new interpreter. Every time.

I've checked and as far as I can tell Eclipse has write access to all the locations where it writes configuration to in my Windows system. I checked the logs, and see the same error repeated over and over:

 - Err output:
Traceback (most recent call last):
  File "C:\Users\me\.p2\pool\plugins\org.python.pydev.core_10.1.3.202301231743\pysrc\pycompletionserver.py", line 6, in <module>
    from _pydevd_bundle.pydevd_constants import IS_JYTHON
  File "C:\Users\me\.p2\pool\plugins\org.python.pydev.core_10.1.3.202301231743\pysrc\_pydevd_bundle\pydevd_constants.py", line 32, in <module>
    _codecs.lookup(_codec)
LookupError: unknown encoding: idna

!STACK 0
java.lang.RuntimeException: Error creating python process - exited before creating sockets - exitValue = (1).
ProcessInfo:

 - Executed: C:\Windows\py.exe -u C:\Users\me\.p2\pool\plugins\org.python.pydev.core_10.1.3.202301231743\pysrc\pycompletionserver.py 58747

I also see the following stack trace sometimes when the error appears:

	at org.python.pydev.core.log.Log.log(Log.java:33)
	at org.python.pydev.ast.codecompletion.shell.AbstractShell.startIt(AbstractShell.java:287)
	at org.python.pydev.ast.codecompletion.shell.ShellsContainer.getServerShell(ShellsContainer.java:240)
	at org.python.pydev.ast.codecompletion.shell.ShellsContainer.getServerShell(ShellsContainer.java:168)
	at org.python.pydev.ast.codecompletion.shell.AbstractShell.getServerShell(AbstractShell.java:219)
	at org.python.pydev.ast.codecompletion.revisited.modules.CompiledModule.createTokensFromServer(CompiledModule.java:377)
	at org.python.pydev.ast.codecompletion.revisited.modules.CompiledModule.<init>(CompiledModule.java:180)
	at org.python.pydev.ast.codecompletion.revisited.modules.AbstractModule.createModule(AbstractModule.java:293)
	at org.python.pydev.ast.codecompletion.revisited.ModulesManager.getModule(ModulesManager.java:1038)
	at org.python.pydev.ast.codecompletion.revisited.ModulesManager.getModule(ModulesManager.java:869)
	at org.python.pydev.ast.codecompletion.revisited.SystemModulesManager.getModule(SystemModulesManager.java:400)
	at com.python.pydev.analysis.additionalinfo.AbstractAdditionalDependencyInfo.updateKeysIfNeededAndSave(AbstractAdditionalDependencyInfo.java:259)
	at com.python.pydev.analysis.system_info_builder.InterpreterInfoBuilder.syncInfoToPythonPath(InterpreterInfoBuilder.java:171)
	at com.python.pydev.analysis.system_info_builder.InterpreterInfoBuilder.syncInfoToPythonPath(InterpreterInfoBuilder.java:97)
	at com.python.pydev.analysis.system_info_builder.InterpreterInfoBuilder.syncInfoToPythonPath(InterpreterInfoBuilder.java:83)
	at org.python.pydev.ast.codecompletion.revisited.SyncSystemModulesManager.synchronizeManagerToNameToInfoPythonpath(SyncSystemModulesManager.java:392)
	at org.python.pydev.ast.codecompletion.revisited.SyncSystemModulesManagerScheduler$SynchJob.run(SyncSystemModulesManagerScheduler.java:257)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

From the command line it says that you've configured C:\Windows\py.exe an the python interpreter, which is definitely wrong.

So, if you configure the interpreter it should fix the idna issue. Now as to why it's not persisting the information, as far as I remember the only case where I've seen this was when a user was using Oomph to save workspace settings and then replicate those settings but then wrongly saved PyDev interpreter settings to nothing in Oomph. Can you check if this is your case?