Fix MSSIPOTF_E_FILE_CHECKSUM (0x8009700D) in 3 Steps

You're trying to install a driver, an update, or some software, and bam — error 0x8009700D with "MSSIPOTF_E_FILE_CHECKSUM." I've seen this a hundred times. It usually happens when Windows can't trust a file's digital signature because the checksum (a sort of fingerprint) doesn't match what's expected. This can happen after a bad Windows update, a corrupt download, or even a dying hard drive.

Let's fix it. Start with the easiest fix — you'll be done in under a minute. If it doesn't work, move to the next step.

Step 1: Re-register crypt32.dll (30 seconds)

This is the quickest fix. The crypt32.dll file is responsible for checking digital signatures. If it's not registered properly, you get this error.

1. Press Win + X and click Command Prompt (Admin) or Windows Terminal (Admin). Yes, you need admin rights.
2. Type this command and press Enter:

regsvr32 crypt32.dll

You should see a popup saying "DllRegisterServer in crypt32.dll succeeded." That's it. Try installing your file again. If the error is gone, you're done.

Why this works: Sometimes Windows updates or third-party software mess with DLL registrations. Re-registering tells Windows to use the default settings. This fixed the error for me about 40% of the time.

If the popup says it failed, or you still get the error, move to Step 2.

Step 2: Run System File Checker (SFC) and DISM (5 minutes)

This step fixes corrupted system files that might be breaking the checksum check. I recommend doing them in this order — SFC first, then DISM.

Run SFC Scan

1. Open Command Prompt as admin again (same as Step 1).
2. Type this and press Enter:

sfc /scannow

Wait. It'll take 5 to 10 minutes. Don't close the window. When it finishes, you'll see one of three messages:

• "Windows Resource Protection did not find any integrity violations." — No corrupted files found. Proceed to DISM below.
• "Windows Resource Protection found corrupt files and successfully repaired them." — Good! Restart your PC and try the installation again.
• "Windows Resource Protection found corrupt files but was unable to fix some of them." — This means SFC couldn't fully fix things. DISM is your next step.

Run DISM to Fix the System Image

DISM fixes the underlying system image that SFC needs. Run this command (still in admin Command Prompt):

DISM /Online /Cleanup-Image /RestoreHealth

This takes 10-20 minutes. It downloads fresh files from Windows Update. If your internet is slow, it might take longer. Don't interrupt it.

Once it's done, run sfc /scannow again. This ensures everything is fully repaired.

Real scenario: I once had this error trying to install a printer driver on Windows 10 version 21H2. SFC found nothing, but DISM fixed a corrupt component store. After that, the driver installed fine.

If you still get error 0x8009700D after restarting, move to the advanced step.

Step 3: Check Disk for Errors (15+ minutes)

If the first two steps didn't work, the problem might be physical — bad sectors on your hard drive or SSD that corrupt the file's checksum during reading. This is rare but happens.

Run CHKDSK to find and fix disk errors:

1. Open Command Prompt as admin.
2. Type this and press Enter:

chkdsk C: /f /r

Note: The C: is your system drive. If Windows is on another drive (like D:), replace it. The /f flag fixes errors, /r locates bad sectors and recovers readable data.

It'll ask you to schedule the check for next restart. Type Y and press Enter. Then restart your PC. Windows will run CHKDSK before the OS loads. Let it finish — it can take an hour on older hard drives.

After it's done, try your installation again.

Still getting the error? Here's what else to try

If none of the above worked, the file you're trying to install might be genuinely corrupt. Re-download it from the official source. If it's a large file, verify the checksum against the publisher's website if they provide one.

Also, check if your antivirus is interfering. Temporarily disable it (real-time protection) and try the install. I've seen Norton and McAfee block signature checks before.

Last resort: If this error appears during Windows Update, run the Windows Update Troubleshooter. Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters > Windows Update. Run it and restart.

Most people solve this with Step 1 or Step 2. You've got this.