Error message during Retrofit: "Corrupt file: missing sub-segment content trans unit with ID..."

Hello!

Sometimes during Retrofit I get this error message: "Corrupt file: missing sub-segment content trans unit with ID...", which makes it very tedious to transfer all the changes that were done in the target translation file into the translation memory manually. I have not deleted any segments in the target translation file, so I´m not sure what sub-segment content could be missing.

Sometimes during Retrofit it will also only import the first half of the segments and leave the other half of the segments untouched. Any suggestions how to handle this error message and Retrofit trouble in general? Thank you!

P.S.: I am using Studio 2017