We have seen some users have database corruption in their Dapper software which causes this.


In order to fix this, we ask that you reset Dapper with the DapperCleaner tool:


    https://www.map-pin.com/_downloads/DapperCleaner.zip


Once you run the tool, all Dapper files will have been cleaned up, and you can re-launch Dapper and have it re-detect your Dap and run through the setup process


If you still have issues after this clean you can re run the cleaning tool and click the button while holding Option/Alt to do a "Deep Clean"

.

Since your music is on your DAP already and your iTunes library is also not changed, Dapper will only sync changes and will not have to re-sync your entire library.