I received an IDML file from translator wich I cannot open with InDesign CC. I received this message: "Cannot open document: mismatched tag"
Is there any workaround?
Sounds like the document is damaged, or was built incorrectly. I would guess the error means that someplace you have an open and close tag that don't match up. This could be because a tag is missing, or possibly a punctuation error, though I'm certainly no expert on the .idml structure.
The only way to fix what you have, I suspect, is to unzip the .idml and look at the component files, find the tag error and correct it. That not something I feel qualified to do, and I suspect it wouldn't be easy for you either. Send the translator a copy of the exact error message you recieved and as them if they can fix it on their end.