Well you have to leave it disconnected from the internet …!

Seems to work fine if you leave it offline … move any files you need off using a USB drive. 

I also have a PC with QB still open which is connected . I leave it permanently running and open. 

Try disconnecting from internet , change date to 1st June. 

Open QB. Does it work ?

Leave QB open and reconnect internet and allow date to sync 

does QB remain open ?

I think it checks system date against licence expiry date when you start QB up. 

Once QB is open. It seems to not check again …

Early days but my offline PC running QB seems happy enough.