Source files made with MadCap contain locked segments... how can I solve this?

I have a project with 144 documents (made with MadCap) and in several files there are segments that cannot be edited. I get the message 'Locked content. Cannot edit locked content'.  When I open one of the documents in Notepad I see that there are the words 'Untranslated' and 'protected' before these segments. However a collegue working with Wordfast can translate and save these segments, but my Trados studio refuses.

How can I solve this problem?

Thanks in advance for your help.

Eva