I lost a large amount of data for more than a year

Not surprised because the server version database is different in that it also has Multi-User access and User-Permmissions and therefore allows for simultaneous access of the database data (see https://www.manager.io/cloud-edition where cloud is similar to server).

Trying to simultaneously access that Server Database by Desktop version or with multiple Desktop instances would eventually result in error(s) such as you state.

Not sure what your point about reverse engineering the database is because they serve different products. Yes, a backup of the database can be shared and it will loose functionality in the Desktop version regarding Users and permissions and these would also not exist if importing the backup from an orginal Desktop edition.

It would have been more clear if I had phrased it “reverse engineering the remnants of your corrupt database file” - it wasn’t related to my anecdote about trying the other version. Just wanted to get that in the forum in case it helped somebody else out who wasn’t using test data.