I ran a scan, about 4 weeks ago and was advised that Avast had found a single rootkit. It was not long after a recent installation of Office 16 purchased from Microsoft directly. It found the file in the Office16 folder, in a wofcompresseddata file. It had a message of Error: access is denied on the Action Result. I happened to be running/scanning MalwareBytes at the same time as the Avast scanning... I ran the Avast scan immediately again and it found nothing. I haven't been using the PC but checking it a few times a week, with updated scanning databases. I have tried Anti-malwarebytes Antimalware, no hits for anything, appears clean. I downloaded their standalone rootkit checker, no hits. I downloaded Norton Power Eraser (NPE), no hits. I have probably ran about 30 scans in the last 3-4 weeks, updating the scanning software and no hits, at any time since. Is this likely a false positive? I have Windows 10 64 Bit. Not using the machine at the moment.
On a second machine, not my own, last week, I had a detection with Avast for a rootkit. This machine is independant of the first machine. Not networked with it. Don't access my emails on it. Don't share software with it. Don't share media/storage devices or use the machine in a personal capacity (someone else's machine). On a second Avast scan, it found nothing. I used Antimalaware and NPE and malwarebytes rootkit scanner, no indication of anything, checked several times. Windows 10 64 bit.
Is it possible there has been a false positive on these machines due to a windows update or similar? I can't find any evidence beyond the initial scans that there has been any issue. Not sure what do do next.
Edit: I ran boot-time scans as well using Avast and NPE and these came back clear.
