Share your experience!
Norton Internet Security has upgraded itself to what I expect is a Windows 10 compatible program (NIS was flagged up by the W10 updater initially as incompatible and then Norton kept advising in pop ups it would get an update to fix that issue)...
Yesterday a new NIS installed itself - flagging up some old ISP software as incompatible and removing it and warning of no othr software or any problems found on install. (The new NIS looks like a renamed "Norton Security" with the software name of the NIS product it replaced)
However on the first reboot of the pc, "MExplorer.dll is missing" and PC Companion is dead - suggests reloading the Sony software 
Is this linked to the update and will MExplorer keep getting corrupted?
Solved! Go to Solution.
Haven't heard about this before. You could try re-installing PC Companion.
I have done since and it fixed it... via an install/repair... but i was worried it would do it again, especially as other things like Skype lost its icon graphic...
Norton said
Removing an item from the Quarantine
You can configure Norton 360 to remove a security risk from your computer. You can use the Restore option to remove the security risk and places it in the Security History Quarantine. Some programs may rely on the security risk item that you quarantine to function. In this case, you can restore the security risk to regain the functionality of a program that requires the risk program to run.
The Restore option is only available for the security risks that are manually quarantined.
In the Security History window, in the Quarantine view, select the item that you want to remove.
Click Restore & Options.
In the Threat Detected window, click Restore.
This option is available for the security risks that are manually quarantined.
In the Quarantine Restore window, click Yes.
Click Close.
and guess what.... that quarantine is full of things from the install including this sony used dll...
now im going through the other 20+ quarantined items to see if i can find what they relate to... some look like "cloud" related so im expecting them to be amazon or WD based...
not happy with norton at all.
Norton's "Suspicious.Cloud.7.L" virus scanner detected it as a threat and quarantied it without asking or warning it found things...
all the quarantined hits are for various S.C codes... i.e. its somehow seeing things NIS never saw as a problem before....
grrrrrrrrrrrrrrrrrrr
I'm glad to hear things worked out for you. Good to know for future reference if other users experience the same issues!

Norton's forum is full of problems from their latest update killing very "normal" software on people's machines as soon as it starts a full scan.