I recently got Samplitude Pro X (use it in 32 bit mode) and my old Nebula Pro 3 (32 bit) that used to work fine in Samplitude V11 is not working. I get this white screen with 01 Mix, 02 MIx....as per the attached screen shot.
Now I re-installed Setup_Nebula3_Pro_1.3.492 x86 and now Nebula does not work on bother Samplitude V11 & Pro X.
There are several issues related to Samplitude Pro X whereof lost GUI is one of them. Giancarlo is working to solve some of the issues, others are related to Samplitude. However, send giancarlo an email, he have an update for Samplitude Pro X 32bit and 64 bit which solves some (most) of the issues The version is named Nebula Pro Client 1.3.500d. In my case this version solved almost all my issues on Samplitude Pro X 32 bit. Running Nebula Pro Client 64bit in Samplitude Pro X 64 bit still have issues (increased/unexpected CPU load) when running more than 8-10 instances or more than 3 in a track chain. I am still testing to find out more.