Some Comcast Xfinity and HBO Go users complain that they suddenly can't watch videos on their PCs

If you are one of the many Comcast Xfinity users getting a weird "Error message: 900106000" when you try to watch videos on your PC, the problem could be related to the latest Adobe Flash update.

Some Xfinity users have been getting the cryptic error message for days, according to a Comcast help forum. Over 150 messages have been posted to the forum, which has been viewed by over 6,000 people.

It appears the problem can be fixed by re-installing an older version of Flash. (Caveat: installing older versions comes with risk, as many times Adobe updates Flash to fix a bug that helps hackers.) There's been another rash of complaints again to the a Comcast forum since earlier this week.

Writes one user:

I am also receiving this message on literally every video that I try to watch. I've tried fixing all the bugs, as per the other troubleshooting information, even uninstalling and reinstalling google chrome. Help!

Writes another:

Just signed up for HBO so I can watch it on my media center PCs.

I get the 900106000 error on two out of the three PC's in my home. Unfortunately the machine that works is my desktop rather than the two PC's hooked up to big screens.

The desktop and one of the others are running Windows 8.1.

The third machine is running Windows 7.

Have tried both Chrome and IE on the two machines that won't work. I am using Chrome on the machine that does work.

Looking for a way to fix this before I cancel the HBO service.

In this latest instance, Ken Fromm, a vice president at cloud infrastructure provider Iron.io, tells us he couldn't watch videos from Comcast for a few days.

Fromm did some sleuthing and discovered that by using Safari with an older version of Flash, things started working again. He also tells us a fix for Google Chrome could have happened, as Xfinity just started working for him again when using Chrome.

With the caveat above about using older versions of Flash, here's how you can go back to an earlier version of Flash in your browser:

1. Go to this page that lists Adobe's Archived Versions of Flash. Scroll down to a version before the problems began and install it.

2. If that doesn't fix it immediately, try uninstalling Flash by going to this page and downloading the "uninstaller." Then reinstall the older version again.

3. If that doesn't fix it, and you are using Chrome (which automatically updates to latest version of Flash) try downloading a new PC browser, such as Safari or Opera. You may need to manually install Flash again.

We've reached out to Comcast and Adobe to comment and will update this post when we hear back.