Hello Dennis,
I am sorry about the issue.
Could I have a copy of the project folder so that I can take a look at whether the issue occurs for me as well, and whether there are available backups to be restored for the project?
You should be able to find the folder at the path displayed in the error window, you can then make a copy of it and upload it to https://www.swisstransfer.com/ and provide a download link to support @ incomedia.eu
Thank you.

Hi Eric,

Looks like I do have backups (see attached image).

How do I restore the backup?

Dennis

Hello Dennis,
I would suggest duplicating the project first of all, so that you can maintain a copy as it is, and then select a backup coming from a date where you were still able to open the project and select "Redo"