Problems reviewing a package in Studio 2015

Question

I received a package for editing, but I get the message shown below and it will not save my changes, the source text is completely locked - I can't even right-click it to copy it. I believe the package was prepared in Studio 2009. The strange thing is that I have translated/edited many packages for this client and have never had a problem before. 
 Any ideas as to what is going on?

Thanks in advance! 
 Dorte

Paul · Answer

Hi Dorte, 
 
Not one I've seen before, but if you can share the file I'd be very interested to see this problem? Not recognising the filetype is fine, but not being able to copy source to target is a new one on me. 
 
Regards 
 
Paul

Paul · Answer

Hi Dorte, 
 
I have the package, thank you. But I don't have any problems with this. I do get the filetype not recognised message as expected, but I can copy source to target, I can copy individual words and phrases to use elsewhere. Nothing is locked for me. I can also edit the target and save the file. 
 
Are you sure you don't have more than one instance of Studio running with this project open (or something like this) and perhaps this is causing the locking? Or maybe you have another process attempting to use the same files somehow. 
 
Maybe the solution will be to take a look at what you are doing via Skype perhaps? 
 
Regards 
 
Paul

Trados Studio > 1. Trados Studio

Problems reviewing a package in Studio 2015