IntelliJ IDEA endless indexing on Windows after startup and when opening projects. Some UI elements do not react on clicks – Support | JetBrains

Problem

IntelliJ IDEA is continually indexing files after startup and when opening multiple projects in separate windows.

Once the indexing completes, other aspects of the UI are sometimes broken. For example, the runner drop down at the top will not open. Clicking the drop down does nothing

In the idea.log log file the following exceptions are observed:

Caused by: com.intellij.util.io.ClosedStorageException: storage is already closed; path C:\Users\<user name>\AppData\Local\JetBrains\IntelliJIdea2023.2\index\stubs\java.class.extlist\java.class.extlist.storage
 at com.intellij.util.io.PagedFileStorage.doGetBufferWrapper(PagedFileStorage.java:460)
 at com.intellij.util.io.PagedFileStorage.getBufferWrapper(PagedFileStorage.java:435)
 at com.intellij.util.io.PagedFileStorage.getBuffer(PagedFileStorage.java:426)
 at com.intellij.util.io.PagedFileStorage.putInt(PagedFileStorage.java:159)

Caused by: java.io.IOException: java.nio.file.FileSystemException: C:\Users\<user name>\AppData\Local\JetBrains\IntelliJIdea2023.2\index\stubs\js.symbol.qualified.names.index\js.symbol.qualified.names.index.storage: The process cannot access the file because it is being used by another process
	at com.intellij.util.io.FilePageCache.flushBuffersForOwner(FilePageCache.java:335)
	at com.intellij.util.io.PagedFileStorage.force(PagedFileStorage.java:493)
	at com.intellij.util.io.ResizeableMappedFile.force(ResizeableMappedFile.java:168)

Cause

Antivirus blocks IDE access to disk, in particular to the IDE caches directory, which is needed for indexing.

Resolution

Exclude from antivirus/firewall scan the IDE configuration and caches directories and the IDE installation directory itself.

It might also be needed to delete the existing IDE caches directory while the IDE is not running and then start the IDE.

See also: Permanent Indexing of Project