What OS? What version of Obsidian? What installer? Maybe show your “Show Debug Info”.
And syncing with that tool?
Have you tried the troubleshooting/debugging steps? (from the Help template.)
The debugging steps
Also depending what OS, if you are storing stuff in Desktop or Documents, check if your OS is set to sync those things. OneDrive in Windows, or iCloud in MacOS. And if it is, make sure all your files are set to be downloaded and locally available. If it’s Linux, I’ve seen a thread or two about black screens.