Security Essentials is giving error when trying to update

Hi:

Yes, the fact that you have not updated Windows with important security patches for "quite some time" may be contributing to your problem.

The free upgrade offer from Win7 to Win10 ended months ago.
There are no more "GWX" reminders.
So there is currently no solid reason to refuse important security patches for Windows and your other MS software (e.g. MS Office).
If you are missing one or more months worth of security updates, your system is vulnerable.

As a general principle (with rare exceptions), one should install at least ALL "critical" and "important" SECURITY updates.
The decision to install "Recommended" and "Optional" patches, especially those that are not security-related, is up to the user. You'll need to read the descriptions of each available patch to determine if it applies to or might be needed for your system.

I do not use MSE.
So I cannot help specifically with the error message you report.
But, for starters, I would suggest running Windows Update manual checks and installing ALL available "Critical" and "Important" SECURITY updates.
It may have to be done in batches, depending on how many of them you are missing.
In other words, do not try to install 20 or 30 security patches all at once.
I suggest leaving ".NET framework" patches for last.

And you will need to reboot several times during the process, when prompted.
It's a good idea NOT to use the computer for other chores during the update process.
And one needs a lot of patience -- making sure KB 3020369 and KB 3172605 are installed (manually, if necessary) may expedite the process.

Please report back and let us know how it goes, so that we can all learn.

Thanks,
MM

Do reply #2 here.

Windows Update will not update and I've tried multiple fixes