We have for some time now been using AVG anti-virus software, and currently have version 7.5 installed on all of the computers here. It has worked well and has been minimally invasive, unlike Symantec's products, which have shown a tendency to be almost as bad as the viruses from which is is protecting us. So, yesterday morning, when the software came up with a free upgrade to version 8.0, I downloaded it without any qualms. I should have had them. After going through the download and all of the hoops of installation, I found to my dismay that my Cisco VPN software would no longer connect. I must have VPN access in order to work remotely, and being able to do this has been a large part of my life these past few years. I tried various things in the program's configuration to see if it would let me connect, including shutting the firewall off completely. Nothing worked. Even when I disabled everything in sight, it still wouldn't connect. This was Not Good.
Fortunately for me, AVG's software did actually let me uninstall it -- unlike Symantec's stuff, which seems to never really get all of its tendrils out of your system unless you go back to "bare metal." I still had the version 7.5 installer on hand, and the license key for it still worked, thank goodness. After getting rid of 8.0 and reinstalling 7.5 (and the huge amount of updates for it), I was very relieved to see VPN running as before, and I was able to get back to work.
As part of the removal process with 8.0, AVG asked why I was removing it, and I explained in no uncertain terms that it was incompatible with software that must work for me. Cisco VPN may be rotten software -- it's so badly written that my registry-cleaner software keeps trying to remove it -- but it's what my company requires, so I'm stuck with it.
Now I have to hope that AVG fixes the bugs in 8.x or keeps updating 7.5 for a while longer.