I noted that the alwil folder located in C/program/ increase day by day, now is at almost 100 mega, do you think there is something I can delete in order to keep just things that really need?
Logs, dumps…
Temporarily disable the avast self defense module:
- Right click the ‘a’ blue icon on system tray.
- Programs settings > Troubleshooting (tab)
- Disable self defense module.
- Delete files here: C:\Program Files\Alwil Software\Avast4\DATA\log
Some of them you won’t be able… - Enable the self defense module back.
There is obviously a reason for this and I wouldn’t even attempt to delete anything, you would also have to disable avast’s self-defence module to do that.
Have you done any tweaking of avast since you have had it ?
The avast logging if you lower the slider you get more info recorded and you can also lower the log file size, Program Setting, Logging.
How long have you had it installed ?
Mine is 83.2 MBs and I’m not unduly concerned.
Why? Tons of dumps files that avast does not automatically collect to analyze?
Why? Temporary error files, long logs not restricted by size/date by the avast log settings? I see really not use on that files for tons of tons of users…
Why because we have absolutely no idea what antonpaco is contemplating deleting. That is why I suggested the logging level and restriction of the log size, which I personally feel better than actually deleting files as you don’t have to temporarily disable the self-defence module.
I have suggested to delete the dumps, so antonpaco could or couldn’t delete them, but your comment came after saying that There is obviously a reason for this, for me, not so obviously… antonpaco wants his HDD space back, I want mine too…
avast is very poor on housekeeping and the self defense module made it ever poorer imho… 
I installed avast on february 2008 and scan almost every 7-10 days. At this point I do not delete any file, I am afraid to make damages.
Well I assume that you have been doing regular VRDB generations, this is usually set for every 21 days depending on your settings. This generates three versions of a database based on the executable files on your system (to help repair if they become infected).
So if you have a lot of programs on your system this integrity database can get large, it doesn’t make copies of the files, just enough information to be able to attempt to put them back as they were. This is all kept in one file, C:\Program Files\Alwil Software\Avast4\DATA\integ\avast.ini mine is currently a little over 6MB, the more programs you have the larger this is likely to be.
The VPS (C:\Program Files\Alwil Software\Avast4\DATA\400.vps) is about 18.5MB so should yours should be similar.
If you have downloaded a lot of skins, I have quite a few and my Skin folder contains almost 9MB of skins.
My avast Log folder is small as I keep the file size restricted using the Loggin settings I mentioned before.
In the log folder you won’t damage anything.
Besides, you can always repair your installation:
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair).