Hi,
Do you use Arturia plug-ins by any chance? There was/is (sorry, I don’t know, if it has been fixed already) a bug in the plug-ins, which causes the project file size increased while using the plug-ins.
Thank you Martin, a very good idea. Not Arturia, but maybe any other plugin. I try to find the difference between the slim and the fat bak-file. I tell you the result. Thanks !!
Hi,
I’m not aware of any other plug-in, which would do this at the moment (for example NI Kontakt did it too in the past). But that doesn’t mean, there is not any plug-in doing this of course.
Do you use Melodyne or any other ARA extension. If I remember, there was (is?) also something similar.
Hi Martin,
unfortunately it is not any plugin. I took out all of them and saved the file resulting in no difference. All what is different to the slim and fat file is that i used the SpectraLayers in Cubase 11 after the slim one. But i closed it correct, took out the loaded file and made tests. Now i have this 149 MB projectfile. Well, i have no idea further. If anyone has equal problems i could exclude that my computer is the reason. Thank you again
Hi,
OK, then this is it. There are some other threads referring to the issue here on the forum.
Btw, SpectraLayers is a plug-in (ARA). 
Hi Martin, sure it is a plugin. I meant aktive in the event plugins. But i could not find any further hint what causes this blow up of the projectfile. I made new Projects, monitoring the use of SpectraLayers but it did not happen anymore. Only at some older projects and it is still there. If you could be so kind and post a link to equal threads for me ? I use the SpectraLayers one what comes with Cubase 11. And thank you again for answering. Franz
…something more. I edited the BAK File to look inside. There are more then 10.000 empty rowes inside. I deleted them. After trying to open it, Cubase reportet a corrupt file. But the file went down from 149 to 5 GB. So it is sure that the empty space causes the amount of GB.
But what is the reason for that ? Maybe a Steinberg Technical Support can clear this ?
Hi,
This is a known issue in the SpectraLayers. Unfortunately you cannot do anything but wait for the fix.