...but then it pops up this messege and says: Wallet file corruption detected. Please restore your wallet from seed, and compare the addresse…
This means that your wallet file is corrupted and could possibly be creating addresses that are not backed up by your recovery seed.
There was
an old issue that was fixed whereby you could end up with a situation like this:
When creating a new wallet, the path would be set to the path of an existing wallet, as due to os.path.exists failing, the wizard would think there is no file there yet. However in the wallet storage constructor, os.path.exists would suddenly work and the existing file would get opened. The wizard would then start modifying the existing file, thinking it's a new one. The wizard would put a new seed and xpub there. Then, the task that creates the addresses for the xpub (create_addresses) would be a no-op, as it would find that there are already "enough" addresses generated in the file (corresponding to the old wallet!).
When the wizard finished, the wallet would then get opened as normally. The wallet file would contain the new seed, new xpub, but old addresses.
It would appear that you might have had something similar happen... You should create a new wallet ("File -> New\Restore -> NEW_WALLET_NAME -> Standard wallet -> I already have a seed"), as suggested by nc50lc... and see if it generates the same addresses as the wallet that is giving you the corruption warning.
If it does not, then your seed will not be able to restore your wallet file. You should immediately create a new wallet (with new seed) and send all your Bitcoins from "corrupt" wallet to new wallet.
