Initially, deleting the entire Byteball directory from the Program Files (x86) directory enabled me to reinstall it and then I chose the full wallet again.
During the synchronization which was very slow, the same exception reappeared and threw me out again.
Uninstallation (which in version 2.4.1 deletes the directory by itself) did not help after this, and now I can not even choose the light wallet since the exception is back to emerge before I have an opportunity to do anything.
RE: Byteball Airdrop to Steemians!