I plan to install Comodo firewall and Avast on my new laptop which is running Vista and I heard a lot of problem if UAC is enabled… Is it safe for me to disabled it cause I find it quite annoying and it is not proven being that effective yet at all =S
I have had UAC disabled for a about a year and would never enable it again. And have now disabled it on a second computer. It interferes with a number of programs (although Avast! is OK with it) and causes various Comodo problems for some users. The culprit is mostly virtual store, although there are also prompts that should be there and aren’t. If you disable it, some programs you have already installed will have some configuration issues, so do it as soon as possilble. Read about the threats, though, by looking with Google. Individual users with internet links seem to be OK without it. BTW, since none of the XP users have it (or want it) and manage to survive, you should also. 
Me one of them 
Little bit off topic: even limited user accounts are useless if you have robust HIPS (like D+ of Comodo), Comodo Memory Firewall and you are experience enough to use them properly. imo.
If you disable UAC, then programs written specifically to detect Vista features will fail – the famous Adobe Acrobat bugs. To install it, you need to right-click on the installer and go to properties to change the compatibility to Windows XP. Then it will install properly. In the future, there will be more such cases. More and more software will detect Vista and expect UAC to be turned on. Thus, it’s better to have it enabled.
To work around the issues of UAC and the virtual store, follow my tutorial here:
https://forums.comodo.com/empty-t20463.0.html
Although, Comodo should really fix all these issues with UAC and fully make CFP 100% compatible with Vista. They need to use the Vista features to write to the actual program files directory instead of Virtual Store. Microsoft has all the documentation on-line, so the CFP devs need to read it and fully detect Vista and use all the features so that it works properly without work-a-rounds. So, this should be the next feature of CFP. It should be too hard to detect Vista and use the sample code they have.
To the devs: There is some nice sample programs here with source code: http://www.tweak-uac.com/ Look at the Vista Elevator and Vista tools on the right side menu.
For users: Tweak UAC will allow you to set UAC in quiet mode with automatically gives admin status without the pop-up, that way you can keep UAC on and thus compatibility with all the Vista specific programs such as Adobe software.
Hope this is helpful and I hope CFP devs read this and get the Vista issues squared away. I will bow down to the devs and call worship them when they do this. (:TNG)
I like to have UAC on for safety. I have enabled the real administrator account for use with Comodo. I can then quickly log in to save my Comodo settings or update Comodo. Everything else works with UAC. All the other software I use works with UAC on.
I have no problem with Adobe Acrobat without UAC, if you mean the Reader. Installs with no special effort-at least they seem to have fixed the bug by 8.1.2. And it is a bug, since the installer should recognize whether or not UAC is active and install accordingly, And I certainly don’t see developers forcing UAC on their customers, considering the resistance it is encountering in the market. Certainly useful for some installations and systems, but not for everyone.
There are still issues with the CS3 suite. UAC needs to be on for it to work right, or put in XP emulation mode, but I don’t like doing that since I don’t know if it will use all the features of Vista. Also, some legacy software has issues with UAC being off as well. Some companies don’t upgrade multi-thousand dollar software very often. 
Some users notebooks may be company notebooks, so advice about turning off UAC needs to be handled cafefully since some users may get in trouble for that so, one should add the clause: If your company permits.
There are business customers on this site, from getting SSL certificates and other paid products, and those companies may use the free software as well, so everyone needs to remember that. We cannot work against any business’ policy here.
I’d have UAC disabled regardless if I had COMODO installed. Since you have COMODO installed you should turn UAC off.
Why?
Dennis
Its quite useless. It mostly protects vital system settings. Of course its better then nothing, but I think its more annoying then helpful.
I run XP and Vista in limited account so in Vista I do not have to go to admin account windows updates etc. with UAC turned on I only use the admin account for major software installs like CPF3.
No choice in XP.
Dennis
I have UAC disabled. Defense+ covers UAC and more with “blocking unauthorized connections”, etc.
Josh.