Same thing is happening to me... It started a few days ago. Everything was working fine and I hadn't made any changes. When I tried to update my accounts, I got a pop-up that said: ' Cloud Account Not Found" Quicken cannot find a corresponding cloud account. Click "Set up a new cloud account" to resolve the issue. You should reconnect your bank accounts if necessary after setup is complete. I tried to "Set up a new cloud account" and nothing happened. I was chatting with Quicken support and the had me export the QXF file. The process starts and I can see the file in the download folder. The last step completes and then the file just disappears from the folder. No crash report. I'm using Quicken Deluxe Mac Subscription, Version 6.5.1 macOS 11.6.1
Same problem here starting a few weeks ago. I continue to enter my transactions but the update is broken. In addition, some of my data may have been corrupted. The balances are wrong in at least a few of my accounts (maybe all of them).