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Software updater creates lc.dat on my Windows Desktop


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Hi, when I close CCcleaner64 after letting it check for software updates a file named lc.dat appears on my Windows 11 desktop, see attached example.
If have to add read access to myself before I can even open it, the contents are unreadable binary and not recognized by any heuristics file type detection service, nor recognized as virus by any virusscanner (used VirusTotal).
Any idea why this file appears? Is this a bug? or is the CCleaner software update scanner hyjackable by some virus?
 

lc.dat

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7 hours ago, Dennis Verspuij said:

Hi, when I close CCcleaner64 after letting it check for software updates a file named lc.dat appears on my Windows 11 desktop, see attached example.
If have to add read access to myself before I can even open it, the contents are unreadable binary and not recognized by any heuristics file type detection service, nor recognized as virus by any virusscanner (used VirusTotal).
Any idea why this file appears? Is this a bug? or is the CCleaner software update scanner hyjackable by some virus?
 

lc.dat 22.33 kB · 1 download

Have seen that file as well on Windows 10 , but it ended up in a documents folder. Had no idea where it came from nor how to view it. Malware and virus scans came back clean. No software was updated.

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Looks like the file is coming from when you use the Registry Cleaner option. the file was not present on my system (had deleted the prior one) when I ran the software updater , but was there when after I used the Registry Cleaner  option. Nothing found that will open it so far.

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Sorry, the name is just too generic to identify;
".dat" indicates a data file, and the 'lc' indicates that it might be to do with a licence?

However I suggest that you stop using the Registry Cleaner anyway, it is not recommended unless you have a specific issue that you are trying to fix.
It's not for general cleaning.

For the official Piriform advice on using the CCleaner Registry Cleaner see this: https://community.ccleaner.com/topic/59952-i-get-a-registry-error-on-ccleaner-on-windows-10-i-have-scanned-5-times/?tab=comments#comment-326804

Here is Microsofts' advice on using any Registry Cleaner:
https://support.microsoft.com/en-gb/help/2563254/microsoft-support-policy-for-the-use-of-registry-cleaning-utilities

*** Out of Beer Error ->->-> Recovering Memory ***

Worried about 'Tracking Files'? Worried about why some files come back after cleaning? See this link:
https://community.ccleaner.com/topic/52668-tracking-files/?tab=comments#comment-300043

 

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@Dennis Verspuij If you have a comment then use the Reply box and not the 'Report' option.

My comment about Reg Cleaning was to Jeff M and not to yourself.

You still haven't replied to my question of what software you were updating?

*** Out of Beer Error ->->-> Recovering Memory ***

Worried about 'Tracking Files'? Worried about why some files come back after cleaning? See this link:
https://community.ccleaner.com/topic/52668-tracking-files/?tab=comments#comment-300043

 

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Shame, I was hoping to maybe tie it down to a particular software update.

As it is the name of the file is just too generic to identify, as I said above.
".dat" indicates a data file, and the 'lc' indicates that it might be to do with a licence?

I have found other reports online of a file with that name suddenly appearing on the Desktop, or in the Documents folder, for people who don't even use CCleaner.

So whilst I can't say for 100% certain that it wasn't CCleaner that put it there - those other reports online from non-CCleaner users, and the fact that no one else is reporting seeing it after running CCleaner, suggests that it's probably coming from elsewhere and it's just a coincidence that you first noticed it after runing the Software Updater scan?

*** Out of Beer Error ->->-> Recovering Memory ***

Worried about 'Tracking Files'? Worried about why some files come back after cleaning? See this link:
https://community.ccleaner.com/topic/52668-tracking-files/?tab=comments#comment-300043

 

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Posted (edited)

Hi, thanks for your answer.
I doubt is is another program writing the file, I can delete the file, run CCcleaner, let it scan for software updates, close it, and then the file reappears, reproducable every time.
But your comment got me thinking, I searched the whole filesystem for another lc.dat and found exactly one in C:\Program Files\CCleaner folder, dated somewhere around install time. On other systems I also see this file in that folder, and it being updated after each scan for software updates.
So it looks like CCleaner is updating that file upon each scan (is it a database?), but that it mistakingly writes it to my desktop instead of the program folder?

Edited by Dennis Verspuij
typos
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Thanks for that extra info, it's interesting.

I'm out right now but will take a look at that when I get home.

You might want to try reinstalling CCleaner to see if that corrects where it is saving the file.

Download an installer from here, I suggest the 'Slim' installer (same CCleaner just a slightly different installer): https://www.ccleaner.com/ccleaner/builds

Don't uninstall first and the reinstall will pick up your existing licence if you have one. (If you do want to uninstall first then make a note of your licence key so that you can re-register after the new install).

*** Out of Beer Error ->->-> Recovering Memory ***

Worried about 'Tracking Files'? Worried about why some files come back after cleaning? See this link:
https://community.ccleaner.com/topic/52668-tracking-files/?tab=comments#comment-300043

 

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Posted (edited)

I think I found the culprit.
The problem happens because I start CCleaner from the Open CCleaner... context menu item of the Recycle Bin icon on my desktop. In that case the working directory is probably implicitly set to my Desktop folder. Instead the CCleaner start menu shorcut has explicit working directory C:\Program Files\CCleaner, if I start using this shortcut the lc.dat in updated in that installation folder as it should. The mysterious recycle bin invocation parameter /FRB does not seem to have any influence in this.
So conclusion CCleaner writes the lc.dat into the working directory instead of installation folder. Or there is something wrong with permissions/UAC and the working directory is used as fallback, because I notice that whether or not I check the Options > Advanced > Skip UAC Account Control warning I will get the UAC prompt nonetheless. I am running latest Windows 11 Pro and do have the CCleanerSkipUAC - myusename task which I think it is supposed to be using to skip the UAC prompt.
Finally I am still wondering what the lc.dat is, is it a results database of scanning software updates, or a license file, and if so, why is it updated everytime, and why isn;t it stored in user appdata? 

Edited by Dennis Verspuij
typos
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Thanks for the testing, that's even more interesting and I'll flag it up. (Don't know what kind of priority it will be given though?)

I don't put that recycle bin option on my installs, never really seen a need for it as CCleaner empties the bin anyway and I hardly ever open the Bin.

As for what the lc.dat file is I haven't a clue, but presumably it's being used by the Software Updater.
(As it appears to change following a scan then maybe 'Local Configuration' data about what software is installed on the machine perhaps?)

The SkipUAC thing may well be a glitch in Win11, there are enough of them that it wouldn't surprise me at all.
Of course it may just be another symptom of launching CCleaner from the Bin context menu, do you still get the UAC if you launch CCleaner another way?
It sounds as if Windows is ignoring the setting in CCleaner, so-
Try unticking SkipUAC and closing CCleaner, then reopen CCleaner, tick SkipUAC again, and close CCleaner again.
Toggling a setting like that can sometimes 'unstick' how Windows is behaving.

*** Out of Beer Error ->->-> Recovering Memory ***

Worried about 'Tracking Files'? Worried about why some files come back after cleaning? See this link:
https://community.ccleaner.com/topic/52668-tracking-files/?tab=comments#comment-300043

 

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Hi, yes I tried toggling the SkipUAC checkbox with intermediate restarts, but didn't help.
I think indeed the lc.dat is some encrypted database of scan results.
Thanks for your time and flagging this issue up, I'll await a next version that hopefully fixes this!

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Did you try an uninstall/reinstall to see if that solves the UAC issue?

If you do try that then 'Run CCleaner' as the last step of the install, that can sometimes solve some permissions problems.

Other than that sorry we couldn't find a fix but at least we seem to know what is causing it.

*** Out of Beer Error ->->-> Recovering Memory ***

Worried about 'Tracking Files'? Worried about why some files come back after cleaning? See this link:
https://community.ccleaner.com/topic/52668-tracking-files/?tab=comments#comment-300043

 

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