Welcome Question,
Thank you for the detailed description. SRUDB.dat is the System Resource Usage Monitor database, which records app usage data in the background. Before narrowing this down, I need a bit more information, and I've included some quick tests you can try in the meantime.
- Which Windows 11 version and build do you have? Press "Windows key + R", type "winver" and press Enter. Are you on a Windows Insider build?
- Are you signed in with a personal Microsoft account on this PC?
- When you say "sfc /scannow" doesn't work, what exact message does it show?
Step 1: Repair the Windows image first, then run SFC
- Right-click Start and select Terminal (Admin) or Command Prompt (Admin)
- Type
DISM.exe /Online /Cleanup-image /Restorehealthand press Enter. Wait until it shows "The operation completed successfully." - Then type
sfc /scannowand press Enter.
Step 2: Turn off Activity history and clear it
- Go to Settings > Privacy & security >Activity history
- Turn Store my activity history on this device to Off, then select Clear history
- Restart the PC and watch whether the file still grows quickly.
Step 3: Install all pending updates
- Go to Settings > Windows Update and select Check for updates
- Install everything offered, including the items under "Advanced options" > "Optional updates". Then restart.
Step 4: Run a Microsoft Defender Offline scan
- Go to Settings > Privacy & security > Windows Security > Virus & threat protection > Scan options
- Select "Microsoft Defender Antivirus (offline scan)" and select "Scan now". The PC will restart and scan
Please reply with the answers above and the results of each step, and I'll continue from there.