i tried to launch with anticheat off and it works(its also working off-voobly too). Therefore -with the help of Dedpool-, i recognized that Voobly somehow detects 'cheat' in my current version of Aoc. So i tried with another version and problem is solved.
Weird thing is I tried with 3 different versions of aoc(one of them was AoE HD with voobly compatibility patch) and none of them were able to pass anticheat. The other 2 versions are the ones that ive used with my previous pcs, they were working fine.
Also another weird thing is when i reinstall the voobly, i can play few games before it fails to launch. Dedpool told me that Voobly detects anticheat during these games and denies the launch after the first few games.
Did you guys update your anticheat lately? Because those versions that are denied by anticheat used to work fine.

The anticheat dll file is slightly buggy at times and is known to produce this error however, this is rare. In your case, I presume the issue is something different. You probably have the prior game instance running in memory (hasn't been terminated or released from memory) before you start a new one. Have you tried opening the task manager to see if the game is running in the background, when this happens? Have you tried relaunching the game again (a second time) after you see the posted error?

The anticheat module performs a series of checks and it failing need not necessarily imply a cheat. While it does check for modified game files, in your case I presume the problem is elsewhere.

no i don't this thats the case because i had players complain same problem at this week ( one of them actually just went ahead and reinstalled windows (after he reinstall voobly few times ) all this happened before asking for help ... and he too tried many aoc versions ( one of them was copied from his old computer that used to run well for years ) and the others are just illegal copies of the game , soo i asked him to run the the anticheat off (test) ) and he was able to launch the game soo i asked him to get a legal version of the game with game setup ( not just use him old copy of the game ) and the problem was fixed too

It is not uncommon for players to download 'untrusted fixes' from 'unreliable sources' when they have a problem. Therefore the concept of anticheat failing to validate the install is not uncommon either. For most users a reinstallation simply means a copy of the files back to a new location or the same location so that has to be taken into account. There is absolutely no doubt that the AC will prevent a player from launching his game should there be modified files that do not match the original game data and language files.

The problem in this case is different since it's sporadic in nature. if you are able to run the game once you surely can rule out the possibility of a corrupted install. Therefore the focus should shift over to other factors. What I have mentioned above is a strong possibility amongst other reasons. In either case this is more likely not a case of altered files but more to do with other issues with the anticheat.

Yes i have tried many times to relaunch after ive seen the error. Furthermore, i tried to delete the previous rec, or even tried relaunching with deleting all the mods. None of them works. Its impossible for me to relaunch after first 1-2 games.
Also im sure that the previous game is terminated in memory.
I've tried an illegal version too, one of my friends sent his version(he is currently playing with that one) and still the same error.
Three different versions that i ve tried before i have found a good one:
-Illegal one that i mentioned above
-Original cd
-AoE HD to voobly comp. patch
All of them have the same issue..

DAMN again the same issue 11. The latest version only lasted for 3 games 11

very odd
not sure without re-reading the post,but you might think of cleaning everything voobly and aoc from the pc. reboot and start again. install to program files[86] with admin privileges etc.

I dont have prog files x86 in my computer, only have prog files. Also no D drive. I deleted everything(even steam and aoe hd11) and tried to reinstall but that didnt work. Every 3 games i have to reinstall the voobly 11. Luckily its easy to reinstall xd