Mac: OneDrive Couldn't Start: Please restart your computer and try again

I can confirm this worked for me and several other employees, though a slightly more involved fix. 

Identify what folders they have syncing before running 

Step 1 — Fully quit OneDrive 

Click the OneDrive cloud icon in the menu bar → Quit OneDrive 

Open Activity Monitor (Spotlight → "Activity Monitor") and confirm nothing named OneDrive is still running; force-quit any strays 

Step 2 — Get to the reset scripts 

Open Finder → Applications 

Right-click OneDrive → Show Package Contents 

Navigate to Contents → Resources 

Step 3 — Remove cached credentials 

Double-click RemoveOneDriveCreds.command 

A Terminal window opens and runs briefly, then closes 

Step 4 — Run the full reset 

Still in that same Resources folder, double-click ResetOneDriveAppStandalone.command 

Terminal opens again and clears out local app state, sync database, and the local OneDrive folder registration 

Step 5 — Relaunch and set up fresh 

Open OneDrive from Applications (or Spotlight) 

Sign in with the Altus account 

Since you're mid-tenant-spinout, double check it's authenticating against the right tenant before you pick folders to sync 

Choose sync scope (Files On-Demand vs. sync everything) and let it re-download