MewTools setup pack and optimizer errors (MT-501 to MT-512)

These are the error codes MewTools shows while it runs the setup pack and the Optimizer. Find the code or the message the app gave you, and the fix is under it. Words in curly brackets, like {name}, get filled in by the app with your details.

The app makes a restore point before it changes anything, so you can always go back.

MT-501: {name} could not be downloaded.

The app couldn't get that part of the setup pack.

• Check your internet.
• Try again.

MT-502: {name} failed the safety check, so it was not run.

The file that came down didn't match what it should be, so the app didn't run it.

• Try again later.
• Don't get these files from other sites.

MT-503: {name} did not install (code {exit}).

That installer stopped with an error code.

• Restart the PC.
• Run the setup pack again. It skips what's already done.

MT-504: Could not make a restore point, so nothing was changed.

No restore point means no changes. Your PC is as it was.

• Free up some disk space.
• Try again.

MT-505: Restore points are turned off on this PC.

The app won't change anything without a restore point to go back to.

• Click Turn on so the app can make a restore point before any change.

MT-506: "{name}" could not be applied.

That one change didn't go through. Nothing else was changed.

• If it shows as partly on, undo it from the Optimizer screen.

MT-507: "{name}" could not be undone.

The app couldn't put that setting back by itself.

• Use the restore point the app made before the change.
• Open Start, type Create a restore point, open it and click System Restore.

MT-508: Tamper protection is on. Turn it off in Windows Security first.

Windows doesn't let apps change Defender while tamper protection is on. You have to turn it off yourself.

• Follow the steps the app shows to turn tamper protection off.
• Try again.

MT-509: Could not change Defender.

Windows refused the Defender change.

• Check tamper protection is off, see MT-508.
• Try again.
• Restart if Windows asks.

MT-510: Could not change the Windows Update setting.

The Windows Update change didn't go through.

• Click Windows default to clear our settings.
• Try again.

MT-511: Could not change "{name}" in startup apps.

Windows didn't take the change.

• Refresh the list.
• Try again.

MT-512: Restart the PC to finish.

Some changes only work after a restart.

• Save your work and restart.

Still stuck

Open a ticket in our Discord (how to open one) and paste the summary MewTools gives you, so we can see what it saw.