Is there really a need to run manual scanner

I wrote a letter to Avast team several months ago, and I ask them bout the frequency of doing manual scan on my pc. I immediately got a response from them and they says that as long as the resident scanner is always enabled there is no need for me to worry of doing regular scans. But still I can schedule a regular manual every 15 days if I like to.

What's your opinion bout this?

Do you think we still need to have a regular manual scans even if the resident scanner is always turn-on? Is it to be considered the same tasks? What really is the big difference of the two?

 

I run a scheduled KAV scan once a week with max settings for archives etc. To date it has not found anything the RTM has missed.
With DrWeb I run one twice per week with max settings. So far it has not found anything missed by the RTM.

 

well sometimes (for some unexplained reason) malware can get thru the resident scanner but then be picked up by the on-demand scanner.

i run a scan after a fresh windows xp install (including all my programs). tho it may not be that often, i think on-demand scans still have use.

 

This seems to be the case right now with VBA32s RTM. In the case of the eciar test file, it was not detected in any form (for me) by the RTM but was detected by on-demand scanning. So yes, it is possible to have a resident scanner fail in which case on-demand scanning is very important.

 

Are these guys ok . They have replied the same to a customer of mine who previously had Avast installed ( Now she has NOD32,by the way) . She has had Avast for a year and they have told here the icon is there and it is spinning , no problem , Avast is ok , no virus . However , before I installed NOD32 on here PC I cleaned her computer from variety of trojans which Avast's on-access hasn't picked up .

I use NOD32 with all components always enabled set for maximum protection and I do scan manually at least once a week

 

It depends on your AV and the way it is configured.

You may have a 'higher' level of heuristics on your demand scanner.

Your AV guard may be set to search files by extention or type, while the demand scanner is set to search all files.

Often a realtime scanner will not be looking into archives while the demand scanner will.

Sometimes you will turn off on-access scanning temporarily while performing a task.

Or you may download something and new signatures that find it may be released at a later date.

Maybe the demand scanner is configured to find Adware or riskware while the guard is not.

For all the above reasons (and others) you may find things on demand that have evaded realtime scanning. So periodic scans are a good idea. Personally I find that I do demand scans far less than I used to and rely more on realtime protection.

 

Just do the first scan when you install AV. After that, leave the job to On-Access scanner. You can do scan later in case you suspect anything. But you probably won't have to repeat it...

 

AVG recommends to doing an on-demand scanning daily by its scheduled task, both in AVG Free and AVG Pro, but I think doing an on-demand scanning once a week should be enough.

If an on-demand scanner finds something on your hard disk this doesn't mean your computer gets infected, the real-time scanner of some AV's don't scan archives in real time (e.g. AVG) so malware (such as trojan/spyware in .cab archives) can get pass the real-time scanner to your cache folder while you're surfing the web.

 

Well stuff in archives is in malign form anyway.

 

The RTM settings, particularly on older machines, may have to be a balance between performance and protection. Therefore, the ALL file setting for the RTM may not be appropriate.

Some AV's have a Smart/Process Only New Files setting ( Dr Web/VBA32 ) which can make the running Guard very lightweight. However, there are slight risks in this setting particularly for newbies. For example, it works fine until you miss a definitions update or turn the RTM off for some time.

So VBA's Monitor gives a warning Window when this setting is selected, while in Dr Web, its SmartMode is now supplemented by "Enhanced Protection Mode" which involves a background scanning engine.

However, in these cases a regular on-demand scan and using the context-menu scan for downloaded files is recommended and is a good backup for the Smart setting. The average computer User, IME, very rarely carries out an on-demand scan and so malware can get through.

KAV 6's Monitor also has this default lightweight mode BUT it can override this setting and checks files with a special algorithm. Further, it flashes up a baloon warning if it has been a long time since an on-demand scan has been carried out. A feature which more AV's need to have, IMO.

 

While Avast is a good AV, i don't think anyone will say it's in the same league as KAV, NOD32.So now you need to ask yourself what kind of user are you - 'low risk'?, 'high risk'?.If your 'low risk' i would still run a full scan once a week.It's not going to hurt is it?.If your a 'trekkie' you know, 'go where no man has gone before' i would install a second AV as on demand only like Antivir- i know your only a freebie-user and run this once a week to make sure Avast is doing the job for you.It's nice to hear the comments from others but it is a question only use can answer- how much security and it's performance verification you need.

 

Personally, I think it's a good idea to do regular manual scans with a product different then your resident scanner.

So, if you have Avast resident, run a manual scan with Kaspersky Online scanner or Bitdefender free. If you have KAV resident, etc.

 

well, 1-2 scans/month will be usefull. Sometimes malwares can pass through on-acces scanenr as said before, or samples could be added after the infection took place. Also you could temporarly had your resident scanner disabled and you got infected then....

 

And what's the difference if something gets pass RT scanner? Later when definitions are added it will get detected by RT anyway. In normal conditions if On-Access (RT) scanner misses it, On-Demand will also miss it...

 

Not with all antivirus softwares . Let's have F-prot as an example . In NT environment (XP , example) its real-time proection settings cannot be changed so it scans only selected file types as well as archive not bigger than 64k . This way its real-time protection can miss some infection . Believe me , it does because before I started with NOD32 , I used F-prot for some years and I know for infection in my computer missed by the real-time but caught by the on-demand scanner

Yes , for the on-demans scans


And also with Avast , see my previous posts here in this thread

 

Honestly. I ask this question of myself frequently. Is just realtime good enough after initial scan? At one time I did a daily one. . To much harddrive grind away imho. So I went to weekly.