File Cache Conflict
If an external process changes a file that was opened and unsaved in IntelliJ IDEA, it results in two conflicting versions of the file.
Prevent other applications from modifying the files that are already opened in the IDE or use the following options to resolve conflicts.
Load FS Changes
Click this button to load the file version produced outside of IntelliJ IDEA, and overwrite your local changes.
Keep Memory Changes
Click this button to preserve the version produced in IntelliJ IDEA and stored in cache.
Click this button to invoke the differences viewer that shows the version in the file system to the left, and IntelliJ IDEA version to the right. You can merge differences as required and load the desired version to IntelliJ IDEA. By default, the cache version is saved.