@Jeremy any update? I have same question. Am assuming that the lack of any posting about this is an indication that Across works fine on Big Sur but I'm about to upgrade a laptop on which I MUST have Across working, and I'm a little nervous – reverting back to Catalina would be doable but a huge pain.
I upgraded to Big Sur the day of public release. No issues whatsoever with Across. I think I had to re-pair it with the machine that it's controlling, but that was it (and honestly don't remember if that was when I upgraded the controller machine or when I patched the controlled machine, an older Mac running high sierra).
Can confirm. I installed Big Sur 11.0.1 on an external SSD to avoid the possible MacBook bricking I've been reading about, and then migrated from my Catalina installation. Across does work; however, I'm plagued with an old issue: I can move the mouse to the client machine but not back to the server machine. I have to turn bluetooth off on the client to get the mouse back to the server, and then turn BT on again on the client to get the mouse to go back. IOW, so far the operation is one-way only. I've seen this before, but it was fixed with a reboot – sadly that's not working now.
Hi, jeglin, Please try to reconfigure these settings on both server and client macs: macOS 10.14 and later: macOS added a new security mechanism to prevent an app from controlling another app without the user’s consent. That is, you are able to register an app explicitly as an exception in the allowed list from ‘System Preferences’. To do this, please follow the steps below: Open ‘System Preferences’, and go to ‘Security & Privacy’ and ‘Privacy’-tab. Click on the lock icon on the bottom left corner and enter password. For keyboard/mouse share, choose ‘Accessibility’ from the left-pane, and then add /Applications/Across/Across Center.app to the right list. For file access from paired devices, choose ‘Full Disk Access’ from the left-pane, and then add /Applications/Across/Across Center.app to the right list.