Since end of July my Anti-virus software AVG Internet Security (Paid version) for Mac is acting weird.  It displays, error message such as

Sample Error message 1

This has happened before and usually few minutes later it recovers itself, but this time even after an hour it didn't.
I ran a virus scan, and at the moment it seemed everything was back to normal, but scan finished too early. 

It usually takes more than an hour to finish, but this time it only takes 3 min, and it was finished. Clearly something is wrong with
AVG software.

Sample AVG Error: We're sorry. There is some problem on our side. We'll fix it as soon as possible.

 After contacting AVG software, I was told to provide screen shots. 

Here's their reply

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Thank you for providing the screenshots. 

We apologize for the inconvenience caused since that you are unable to attach the screenshots while providing the issue details and query details you have provided is not attached to the email.

Upon reviewing your screenshots, it seems the AVG Internet Security installation has corrupted. Refer the following articles to reinstall AVG Internet Security for Mac:
Uninstalling AVG AntiVirus and AVG Internet Security from Mac

Installing AVG AntiVirus and AVG Internet Security on Mac

Activating AVG Internet Security on Mac

Your activation code to activate AVG is:
xxxx-xxxxxx-xxxxxxxx-xxxxxxx

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 IF you are new to Mac, Command + Shift +3 
for entire screen or Command + Shift + 4, for portion of screen shot.

It was supposed to be an easy un-installation and re-installation, but it turned out little trickier than I expected.
You see, something went wrong during un-installation, and I couldn't re-install the software.

For Windows PC, it is very obvious that some left over file(s) or folder(s) was/were remain in the system, but on Mac, I just
couldn't locate where they are.   For this, I have to contact the software manufacture again to find where software remains, but
that for another story. 

Thank you for reading.