Today, two Avast Full Scans got stuck twice on files at 95% and 96%: Boot\BCD and one other file.
A boot scan went thru OK as did a quick scan.
I also ran Malwarebytes with no problems or issues. This happened once before, also on full scan.
What gives?
Thanks!
Are you using the default scan or a custom scan?
What are your scan settings?
How often is this happening, everytime or once in a while?
Thanks for your reply… This just started.
Win7 64 Bit, online armor.
Once last week, twice today:
Default Full Scan as follows:
All HD
Rootkit full scan
autostart and modules in memory
scan all files
content
High heurisitcs code emulation
testwhole files
PUPs
Follow links
Thanks again…
Try the default scan without the PUP, rootkit full, autostart, modules in memory, high heuristics, test whole files, scan all files, content. Set heuristics to normal.
Default quick scan settings:
Full scan:
Better now?
Manual scans inspect inert files stored on the hard drive, opens them, and scans contents and other data in memory. The modified settings you are using do not provide any increased protection over protection provided by real-time scanning when any file is called for and run. Manual scanning is much depreciated over real-time scanning as that is your primary defence against malicious files. So, it is the real-time scanner that really protects you, not the extensive modification of default scanner settings.
I run a quick scan at default settings once a week only. See above.
[EDIT:] Fixed typo.
Yes, so far so good… went thru OK…thank you!
I learned alot from your reply, however some questions:
Again, my thanks
I found that “follow links” during a scan is a bad idea.
I use “scan in order found on HDD”. This seems to speed up scans.
PUPs are not necessarily bad. Some PUPs are good, some aren’t.
PUPs are disabled by default due to the fact most users wouldn’t know good from bad.
Weekly quick scans are plenty. avast has real-time shields for better protection, which means frequent scans are not necessary.
If your daily “multi-scans” come up “good” that is a sign you are over-doing it.
Allow avast to populate the persistent cache for quicker scans in the future.
For “boot scans” just use the default settings.
Too much tweaking leads to disaster.
Too many scan means you are using too much computer resources.
I do a “scheduled” weekly quick scan and a full scan once a month if I remember to run it.
My full scan is “not scheduled”. So sometimes I go five weeks or more without running a full scan. 
edit: Boot scans should “only” be done if avast recommends doing so.
I haven’t ran a boot scan in years.
Thanks again…
I always thought you had to scan after each session to make sure something bad didn’t sneak in. Same thing for PUPS - you might accidentally have them on your system from innocent bundled software downloads… scanning would catch this.
I appreciate your advice on boot scanning… was never sure if this was a good idea.
Anyway, I changed all my settings to yours. Maybe someone could put a sticky up on suggested settings for optimal protection?
1.) No scan needed after each session. Real-time scanning differs from manual in this one important aspect: Any file or executable is scanned in the background automatically, at the moment it is run, and without user intervention, when it is called for and run on your system. Think of it this way; avast! is already doing all your scanning for you without you having to do anything. (See point #4)
1a.) PUP’s are Potentially Unwanted Programs. Because they are categorised as software that can be used for good or ill, antivirus programs do not block installation of them automatically, and thus allows user discretion as to whether the particular program should be on their system or not. It’s up to the user, not the antivirus program, to decide.
2.) Boot-time scanning can be dangerous to your system. Use it only when recommended by avast!. Always quarantine, never delete, if the first option is available. Otherwise, choose ignore and quarantine, if possible, later. Windows system files should never be deleted or quarantined, even if infected. Come here for help if you encounter such a situation. Otherwise, you’re looking at a damaged operating system and one that may not boot again if you choose either one or the wrong option.
http://antivirus.about.com/b/2007/03/11/clean-quarantine-or-delete.htm
3.) User decisions and choices affect the integrity and validity and safety of Windows to a far greater extent than some users realize. Visiting adult sites, using torrents without educated discretion and choices, running cracked software, visiting poorly rated sites, etc., all of these, and more, affect whether or not your system will remain clean after a session, or any session, for that matter.
4.) A/V’s cannot protect the user against everything out there. New malware is created every day, every hour, and every minute, to get around a/v defences. Both manual scanning and real-time scanning are both ineffective against this strategy created by miscreants every day.
Heuristic scanning helps, but the highest level brings with it the risk that a known clean file will be tagged as infected when it is not. That can be a problem you can do without.
5.) Two add-ons (extensions) for every browser you use is recommended to complement a/v protection:
https://www.mywot.com/
https://adblockplus.org/en/firefox Tho the link is for Firefox, if you look by the ‘Install for Firefox’ green button, you’ll see other major browsers are supported and protected by AdBlock Plus.
-WOT covers point # 3. WOT blocks poor sites, and also rates software distribution sites, so you can decide whether you want to visit, or if it is safe or not to do so.
-WOT also helps with point # 1a.
-AdBlock Plus helps cover some of point # 4. It blocks malicious ads and adware code so you will never see them in your browser. Plus, your browser will load a page much faster whilst protected, as much less junk is called and allowed to run in your browser window.
To sum up, real-time scanning is noted when a pop-up window pops unbidden in the lower-left corner of your desktop; it almost always announces that a file has been automatically been blocked to prevent harm or damage to your system. Manual scanning will find dormant and inert files on your hard drive (not running) that have data in them that may or may not match known malware signatures.
I’ve seen such manual detections occur very rarely, once in a blue moon, and most of the time, they are a result of a false positive detection.
Damage to your system can only occur when a malicious file is run. Damage cannot occur when a malicious file is not running and is just sitting there. The only time an inert malicious file can damage your system is when you open it, or when another system process is linked to it calls it and causes it to open and then runs from there.
It is primarily for the above reasons that manual scanning is much depreciated and of little value for protection from a safety security standpoint. If one wants an a/v that is only a manual scanner, think ClamAV. It offers no real-time protection whatsoever.
See my sig below for some ideas on what to run to complement a/v protection already in place.
Many thanks once again!!! I will study this and implement what you say. I practice safe computing - no x rated sites, I am super careful what I download, I make sure no bundled software gets thru and I read all reviews on new software prior to any downloading. No P2P and I use Adblock and Better Privacy. I will look into WOT. I avoid use of Explorer, only have it on the system for work -also got rid of Java a long time ago.
Again, I deeply appreciate your sage advice.
You’re welcome.
+1 We’re more than happy to help!
Let us know if you have any scan/avast issues in the future.