[System.InvalidOperationException]

ah yes, there was an integrity violation somewhere, let's  see if this scan fixes.

 

It's on installation, by the way

EDIT: looks like it's working!

[System.InvalidOperationException]

That's not the same issue. I'll split it into it's own thread.

 

System specs?

 

Paint.net version?

 

Give us something to work with.....

Windows 7 SP1, trying to install version 4.0.9. I repaired the .NET framework, so that wasn't the issue...

[System.InvalidOperationException]

Having the same issue...