Had to reformat my 2017 Macbook Pro. That re-installed High Sierra. Update to Mojave worked fine as well. Now trying to go to Catalina (or Big Sur) i get a checking (null) error and the installer essentially freezes here.
I have spoken with multiple support reps and tried all of the recommended fixes.
Has anyone found a workaround or fix to this issue? Seeing multiple threads open that haven't been solved.
MacBook Pro 13″, macOS 10.14
The check NULL error message is sometimes related to an Existing Installer ( failed ) still present on the computer either in the Download Folder or and in the Applications folder. In either case - suggest exploring this and if present, drag and drop to trash and empty Trash
To start again to grab either of the to afore mentioned upgrades - suggestion. Restart in Safe Mode Shift key immediately at restart. For best results. connect via Ethernet Cable to Router. Once operational How to get old versions and using Safari ( again best results ) commence to download again.
'Checking (null)' during mac OS update
