It appears you have files or directories locally that have a different CaSiNg (lowercase, uppercase) than the version you are trying to sync from the server. You need to rename them to their correct CaSiNg or undo the change to them.
The Command Line Tool would be able to tell you exactly which files / directories are clashing.
Set up your environment for working with the CLI, then:
- Go to your project directory.
- Execute
urc.exe project snapshot get
Then inspect the output.