Cannot save/save as project anymore

Since the latest RW update I can’t save the project anymore. I’ve read possible solutions for this problem and tried them all (except for copying the site page by page to a new project, which will be quite a job) so I’m hoping for another solution but no luck since. Anyone out there that has a/the solution?
I’m running MacOS High Sierra and RW 7.5.1

Yeah, I can’t back up since the update and I can’t publish any updates to my website either. It freezes if I try to publish and gives this error message: Upload failed (at start/before it took off). URL: No problems at the server evident. Attempts to back up freeze too.