Fix ERROR_WRONG_EFS (0X00001775) – wrong encryption driver

What this error means

You try to open a file — maybe a Word doc, a text file, or something you encrypted years ago — and Windows stops you cold. ERROR_WRONG_EFS (0X00001775) says: "The file was encrypted with a different encryption driver than is currently loaded."

This usually happens after you upgrade Windows (like from 10 to 11), reinstall the OS, or switch hard drives. The file was encrypted using a specific Encrypting File System (EFS) driver that's no longer active. The encryption key might still exist, but the driver that knows how to talk to it is gone or mismatched.

I've seen this on corporate laptops where IT pushed a new image without exporting the old EFS certificate. Also on personal machines after a fresh install where the user forgot to back up the EFS keys. If you didn't export your certificate before reinstalling, you might be stuck. But let's not panic yet — try these steps in order.

Step 1: Quick fix — restart the EFS service (30 seconds)

Sometimes the driver just needs a kick. The EFS service might have stopped or gotten confused after a system update. Here's how to wake it up:

1. Press Win+R, type services.msc, and hit Enter.
2. Scroll down to Encrypting File System (EFS). Right-click it and choose Restart. If it's stopped, click Start.
3. After it starts, right-click again and select Properties. Make sure the startup type is Automatic. If it's not, set it to Automatic, click Apply, then OK.
4. Now try opening the file again.

If this works, you're done. If you still get the error, move to Step 2.

Step 2: Moderate fix — import your old EFS certificate (5 minutes)

The real problem is usually a missing or wrong EFS certificate. If you still have a backup copy of your old EFS certificate (a .pfx file), we can import it. If you don't, skip to Step 3 — but first, check if the certificate is still on your machine but just not loaded properly.

1. Press Win+R, type certmgr.msc, and hit Enter.
2. In the left pane, expand Personal and click Certificates.
3. Look for any certificate with "Encrypting File System" in the Intended Purposes column. If you see one, right-click it, choose All Tasks > Export.
4. Follow the wizard to export it as a .pfx file (choose to export the private key). Set a password you'll remember.
5. Once exported, right-click the same certificate and choose Delete. Then right-click Personal > All Tasks > Import, and import the .pfx file you just exported.
6. After importing, restart your PC and try opening the file.

If you don't have any EFS certificate at all, you can't do this step. Go to Step 3.

Step 3: Advanced fix — force the correct EFS driver with a registry edit (15+ minutes)

This step is for when the certificate is there but Windows loads the wrong EFS driver. I've seen this happen on machines that had multiple encryption tools installed (like BitLocker plus third-party software) that messed with the EFS driver binding. Let's fix the registry directly.

Warning: Editing the registry is risky. Wrong changes can break your system. Back up your registry first: open Regedit, click File > Export, save the whole thing. If something goes wrong, double-click that backup to restore.

1. Press Win+R, type regedit, and hit Enter.
2. Go to this key:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem
3. Look for a value named NtfsDisableEncryption. If it's there, double-click it and set the value to 0. If it's not there, right-click in the right pane, choose New > DWORD (32-bit), name it NtfsDisableEncryption, and set it to 0.
4. Now go to:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\EFS
5. If the EFS key doesn't exist, right-click Windows NT, choose New > Key, and name it EFS.
6. Inside the EFS key, look for a value named EfsConfiguration. Set it to 1 to enable EFS. If it's missing, create a DWORD called EfsConfiguration and set it to 1.
7. Close Regedit and restart your computer.

After the restart, try opening the file again. If it still fails, the driver mismatch might be baked into the file itself. In that case, the only way to recover is to find the original machine that encrypted it and decrypt it there. Yes, it's a pain. That's why I tell everyone: back up your EFS certificate and key before reinstalling Windows. Always.

Still stuck?

If none of these steps work, the encryption driver used to encrypt the file is simply not available on this system. You'd need to restore the original Windows installation (or a full disk image) that had that driver. No shortcut around it. Sorry.