lscache.dat constantly writing since update to 18.2.3827.307

Avast Free Antivirus / Premium Security
1

I have 4 Windows 10 PCs (current and fully patched) running Avast. Since the last update to the current program version, a file called lscache.dat has been writing constantly on all PCs (somewhere between 300kB/s-3MB/s).

I’ve tried deleted lscache.dat in safe mode but it comes back after a full reboot. It only stops writing when I turn the file shield off.

It looks like this has happened in prior versions as well (based on google searches).

Anyone else seeing this?

2

it’s normal for avast. That’s why I don’t like it.

the solution is, you should disable “transient caching” in file shield settings

3

Where are you getting the stats that Avast is constantly writing that much to lscache.dat?

4

I see it in resource monitor

5

Could you show a screenshot so I can get this escalated to the Avast devs?

6

attached

7

I’ve already posted it on the developers channel but there hasn’t been any response.

8

@nigeltufnelny: thanks for report, I have some additional questions:

  1. what’s filesize of lscache.dat
  2. can you please check filesize again after ~10sec (is it growing, or reducing?)
  3. is it possible send me your lscache.dat (compress if needed, e.g. ZIP, RAR or 7zip) to kurtin@avast.com?

Thanks

9

Hello,

a) it’s about 8.5MB on this computer but varying sizes on my other 3 PCs
b) size is static
c) will send now

10

anyone else seeing this?

11

Confirmed. Avast lscache.dat is active. Write speed varies from 1,000 KB/sec to 20,000 KB’s. Almost continuously active.

12

I’m also seeing this in all of the machines I have

Therefore, I always disable transient caching so it never happens again
it increases disk lifespan a bit

13

Hi guys, thanks for the bug report - we will fix this issue and release an emergency update on Monday.

14

Thank you for addressing the issue.

15

Hi, just wondering when this fix will be released? Thanks…

16

fix was released ~10days ago (uupdate no. 360 – HKEY_LOCAL_MACHINE\SOFTWARE\AVAST Software\Avast\MicroUpdates)

17

Thank you.

18

Hi,

Sorry to bump this but we’re seeing an identical issue with 18.5.2535 (build18.5.3931.0) where lscahe.dat is constantly writing at a couple of million bytes/sec as seen in the attached screenshot.
I checked that registry entry mentioned above and I don’t see a micro update 360 in there - could that be the issue? If so, how do we fix?

19

Another bump here, I am afraid. A constant 30MB/sec with 18.8.2356 (build 18.8.4084.0). I ran and uploaded the report with your support tool. Hope it helps.

…although … it IS possible that the “Resource Monitor” is not reporting accurately. Just because it says that my disk is constantly writing 30-50MB/sec doesn’t mean that it is. First note is that I/O Priority is background. Second (and important) note is that “Task Manager” does NOT report the same number. Task Manager reports nominally 0%, I see Avast show 0.1-0.2 MB/sec occasionally. And for about 5 seconds every 30 seconds it says that System is running at a few hundred MB/sec.

So I don’t think the lscache.dat writing is constant. It bursts foevery 30 seconds.

I turned off transient caching in the file shield and it did NOT fix the problem, including after reboot.