Windows 10 - Defender Offline Scan not working

According to windows Update I am totally up to date - however WDO does not run

Hi Mav,

Sorry I misspelled your name in my previous post.

What you describe as your symptom sounds the same as this.

Cant Start Defender Offilne

Have you tried running a Defender Quick Scan to completion?

Regards,  Glen

Hi Glen - my apologies too - I misspelled your name.

Firstly thanks for that link - that perfectly describes the issue I am having - I took the following steps:

1. Ran a quick scan - this ran to completion (no threats found)
2. Shut down my laptop using a command line: "shutdown.exe /s /t 00"
3. Started up again and tried to run WDO - same issue persisted

further to this:

1. I managed to open the old windows defender interface and saw a trojan in the quarantined field - I removed this:

2. I managed to run the Microsoft Safety Scanner

https://www.microsoft.com/en-us/wdsi/products/scanner

I ran a full scan over night - this morning the results showed that all threats had been found and dealt with - the above Trojan was back in Quarantine - I have since removed it again.

Weirdly when I run the scan through the new interface through settings (image below at the end of text) - no threats are found in both the full or quick scan. 

My next steps will be to try the following:

1 . Get a USB Key to try and run WDO on startup - (although you have said this has since been disabled in the latest update)

2. Run full scans again with:

• Old WD interface (pic above)
• Microsoft Safety Scanner (linked above)

3. Google to check for the best free third party antivirus software and run a scan and WDO equivalent scan
4. Last case - Refresh my PC - reinstall applications

Thanks again for all your help - please let me know if you have any additional tips on the above and/or need any other information from me.

Mav

Just an additional note - I have malwarebytes installed and ran a scan with this (including for rootkits) - nothing was found - this scan has been run multiple times.

Hi Mav,

Sorry to hear completing a scan didn't help. It worked like a charm

for me! I wonder if turning your machine off, before testing WDO

might have undone the scan completing magic. We can't know

what the condition is in the program that caused the problem,

nor whether the scan fix would be undone with a power down,

before trying WDO again. I would recommend trying it again,

without the power down, before resorting to re-install.

Using the USB method is really what's called for here, since you

may still have a malware problem that could be involved.

If you have access to a Media USB that was created 2 or 3

weeks ago, you may be able to get it to work. The current

problem (0x8004cc01) occurs using a USB that has had WDO

"updated" recently. If you update an old USB without formatting

it first, only the definitions are updated. WDO should be left intact.

If a recent WDO modification is at fault, this should alleviate. I

don't have an old level Media USB to test.

ps.. Before reinstalling, have you tried using DISM and SFC?

Use SFC / DISM to repair system files

BitDefender has a Rescue Disk that resembles WDO.

BitDefender Rescue Disk

Good Luck,  Glen