Cubase 8 can no longer open some cprs

I run Cubase 8 on a Mac with OS Yosemite and switched because of a plugin between 64bit and 32bit mode. Since then Cubase is unable to open some cprs. It looks like it will open the project but then it simply does nothing and it won’t recognise any of the cprs any longer. After that I have to cancel the process and start over to open at least some of the cprs that still work. What’s wrong, how can I stop this?

Got it: I have to click on the open button again after it didn’t open and then it works. Still a bug I don’t need.