Some Files Could Not Be Scanned. Help!

[mindy66]

Hello,

Avast is new to me. Have run 3 or 4 scans since having installed it.

Keep getting "Some Files Could Not Be Scanned." What should I do? I've no idea. Not very computer literate.

Here are the 4 files:

C:\RECYCLER\S-1-5-21-842925246-1965331169-725345543-1003\Dc2.exe|TESTCD.NRG

Error: The file is a decompression bomb. (42110)

Please help.

Thanks very much!

[DavidR]

You only actually only showed 1 file and its location, Dc2.exe|TESTCD.NRG, the TESTCD.NRG file is inside the Dc2.exe file.

- Files that can't be scanned are generally just that, not an indication they are suspicious/infected, just unable to be scanned.

Many programs (usually security based ones) password protect their files for legitimate reasons (and avast doesn't know the password or have any way of using it even if it did know it).

By examining 1) the reason given by avast! for not being able to scan the files, 2) the location of the files, you can get an idea of what program they relate to. You may need to expand the column headings to see all the text.

If you can give some examples of those file names, the locations and reason given why it can't be scanned might help us further ?

So without detailed information we can't give a specific answer.

- Decompression Bomb, a file that is highly compressed, which could be very large when decompressed. This used to be a tactic long ago to swamp the system, also see http://forum.avast.com/index.php?topic=15389.msg131213#msg131213.
 
The name really is the most dangerous thing about this and I wish they would change it or simply not report it, a real PITA.

So my recommendation on this one is to empty your recycle bin.

[Pondus]

as David say, empty the recycle bin...do a new scan and i guess the warning is gone

[cestapleton]

On a Windows 7 system, Avast 6 Boot Time Scan reports "some files could not be scanned" and identifies the following 3 files as "a decompression bomb": C:\OEM\Preload\Autorun\APP\Acer Backup Manager\Data1.cab (also mui.exe & mui.exe1). The Backup utility does not continue past 25%, and the system has never been backed up. Fix possible?

[DavidR]

I don't know why you are doing a boot-time scan ?
Generally there should be no need to do that unless avast can't deal with an infection with windows running; then avast would normally recommend a boot-time scan.

If in doing a boot-time scan it is very thorough, looking for PUPs and anso scanning Archives by default, this is where the decompression bomb comes in, very large archive files.

- Decompression Bomb, a file that is highly compressed, which could be very large when decompressed. This used to be a tactic long ago to swamp the system, also see http://forum.avast.com/index.php?topic=15389.msg131213#msg131213.
 
The name really is the most dangerous thing about this and I wish they would change it or simply not report it, a real PITA.

These highly compressed files are generally 'archive' files which are inert, don't present an immediate risk until they are unpacked. If you happen to do a boot-time scan OR select 'All packers' in your regular on-demand scans then you are more likely to come across this type of thing. Personally it is a waste of time scanning 'all packers' and that is why it isn't enabled by default.

[cestapleton]

Thank you, DavidR, for reply and information. The boot time scan ran automatically after start-up problems (now resolved, however). With backup utility not working properly and no first-time backup previously established, the significance of the affected Backup Manager files seemed to contraindicate simple deletion. Is there remedy that would address the apparently benign alert and restore the effective operation of backup?

[Pondus]

are you saying the detection happens every time you do a backup ?

[cestapleton]

Pondus, thank you for your inquiry. Have never been able to backup the system (I presume the files I noted are corrupted in some way, as Avast only alerts about what it cannot scan). The boot time scan was apparently initiated by an internal prompt indigenous to Avast in response to a start-up problem not resolved.

[villandra]

Mindy, the recyclers folder is your recycle bin; try emptying it.

[bob3160]

The boot time scan was apparently initiated by an internal prompt indigenous to Avast in response to a start-up problem not resolved.

The Boot time scan is something you schedule.
Once scheduled (by you) it can be started immediately or at the next time the system reboots.