Question Database Error in Migration from PGV

Hello
I want to migrate from PhpGedView 4.2.4 to webtrees 1.7.9. The setup has worked and I use the same database.
After starting the migration, I always get the same error at about 81%
SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '1-M3' for key 'PRIMARY'
I have already checked with all users the mail addresses and with two missing mail addresses, these both PGV, as well as registered in the database.
I could not find another error. Also, the expression was not found in the PGV tables.
I have already repeated the installation and migration 4 times, but always get the same error in the same place.
Can anybody help me further?

You have two media objects with the same internal unique ID (called an "XREF") - both are called "M3" (or "m3").

Perhaps look in the PGV media table (pgv_media??) in the database and look for these duplicates?

Perhaps export, and then import the data on PGV before migrating to webtrees? This can fix many problems.

Thanks for the hint, I will check the media table.
For the installation of webtrees, I have exported the PGV database and imported into a new database. Then I connected PGV to this new database.
The errors in the media table were apparent not fixed.

> For the installation of webtrees, I have exported the PGV database and imported into a new database. Then I connected PGV to this new database.

Sorry, I meant export from PGV to a GEDCOM file, and then import this GEDCOM file back into PGV.

Oh, ok. Thank you, I will try.