Cannot package file for printing while files "are locked"

[Taniko]

Indesign won't package my book, saying "Cannot save a copy of "FileName" and then "FileName" is locked and cannot be added to book file!"

I did nothing since last packaging, but noticed once, when I was saving files (or the entire book?) some message related to "cloud document" appeared - I didn't pay attention, but maybe I pushed some button wrong occasionally...

How can I correct it? PDF file is being generated without problems, only Packaging for print doesn't work.

Thanks in advance for your help

[Mike Witherell]

What might happen if you made sure all your documents were stored locally on your hard drive instead of on the cloud?

[Taniko · Accepted solution]

Of course I checked it, they are still on my local drive. But I think I have found the reason - there was simply not enough space on the local drive to copy files to the package. Once I freed some disk space, the problem disappeared. Anyway, thanks for your answer.