Backup Catalog in PSE15 results in 2TB+ data

Hello, I am trying to move PSE15 (app. 30.000 pics and videos with 186 GB) to a new laptop using backup/restore of the catalog.

PSE is saving some files several hundred times eg. one video of 1 GB size is saved 242 times in the backup directory. Other

files are still saved several times while others are saved only once.

All my pics and videos are only 186 GB but the backup stops with an error after 2 TB because the USB drive is 100% full.

The drive is only used for this very first backup of the catalog. I checked the catalog, optimized it an created new indices. No success.

All files are stored in the standard windows picture library. The size of the catalog is 175 MB and the catalog cache is 1.9 GB.

Has anybody got an idea what's wrong??????