I'm trying to svn update
my SVN working copy with TortoiseSVN but the update fails, asking to perform the clean up first.
However, the svn cleanup
fails too stating that a \.svn\pristine\20\20long-namecbf.svn-base file cannot be found
.
I've already tried to release the lock but this does not work either.
Any idea how should I proceed?
You can use SmartSVN to restore lost pristine file.
Download and install it. It's not free but 30 days free trial should be enough to repair your repository.
Open your working copy in SmartSVN. To repair, select Modify > Validate Admin Area...
Enjoy!