Hello,
If your project file is too big the export to QCP will not work. HP doesn't recommend over 4GB files for eport and import from QCP. Anything above that size and the recommendation is to back up the DB and restore into the new DB and then to copy over the repository after backing it up as well. During the import/ export operation the temporary folders will hold copies of the files/ folders until the procedure is completed, after which the system will clean them up and delete them, so essentially you are making a copy of the originals and then making a new project from them, so a rule of thumb is too have at least 2 times (an this is the bare minimum) of free available space to make and store the copies sufficiently during the process.

If the process fails during the procedure then the files will remain and need to be manually deleted/ cleaned up from the folders.

Hope this helps,
Dan