Disable Windows 7 Thumbnail Cache - Solved ?

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Telephone Sanitizer (2nd Class)
Staff member
XP used to cache thumbnails in "thumbs.db" files added to the folder in which the relevant pictures were stored. That was logical.
Since Vista, Windows is now using the C:\Users\Yourname\Appdata\Local\Microsoft\Windows\Explorer folder.
This is a known security hazard to those working with confidential images which now get stored on any computer used to view them, rather than kept in the confidential folder.
MS has provided a group policy to counter this exposure, but unfortunately it doesn't seem to work.
In my case, security and confidentiality aren't the problem, but I don't want thousands of cached thumbnails clogging my system for every "guest" image folder viewed on my PC.
Every family or friend holiday snap viewed on my PC generates a thumbnail, which persists forever, when the guest flashdrive/SD card has long since departed.
My PC might be over 3 years old now, but it's still plenty fast enough to generate thumbnails on the fly if I want to see them, so I've attempted to use the W7 facility to disable the cache.
I've use GPE and Regedit as evidenced in the attached, and I've even tried the technique mentioned here
but none of it works.
If I use disk cleanup to delete all thumbnails, then view folders containing images, the cache fills up once again with every new thumbnail.
Has anybody got this to work ?
What have I neglected to do ?
Or is W7 just broken ? again ?


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I honestly don't know what to tell you - you seem to have researched it very well!

If all you want is an invisible app sitting in the background clearing that folder in real-time..........
I hate the fact (from XP onwards) that no matter how hard you try to organize your own data, Windows finds ways to fill your C disk with junk behind your back.
My philosophy on W95 and ME was to install the OS on C, and as far as possible keep all user data, apps, files, downloads, IE cache, everything, on my user partitions, leaving the C disk "as new" barring WUD changes.
That worked so well that I had the OS in a couple of gigs with virtually no free space, easy to keep lean and mean.
When I first installed XP, it wasn't long before I had to reinstall and completely change philosophy as it clagged up to 100% in no time.
Nowadays I wouldn't dream of installing the OS in less than 50Gb, and I still try to keep user data in my user space, but W7 insists on dumping its secret junk all over my OS, and gives me no option to move it somewhere more suitable.
It's easy enough to "Disk Cleanup", but since this disable thumbs feature is supposed to work, it's becoming an obsession to make it work.
In theory, with the group policy set, it shouldn't even allocate the files, but if I go into Linux and delete them all (windows won't allow it of course), then reboot W7, they're instantly recreated even before getting within a mile of any image file, and the first thumbnail generated is instantly cached despite every effort to make that impossible.
I really dislike the way every new OS takes more control out of the hands of the user.
Whose PC is this ?
This might work:


Theres also this neat folder automation utility for Windows. Setup a rule to delete the contents of the folder thats x days old for example.
The "never thumbnails" selection is no good Jus.
I want the thumbnails, I just don't want them cached on my C disk.
On XP I didn't mind the cache, because it resided with the photos in the appropriate folder, and if a thumb became out-of-date because the photo had been processed/cropped etc, it was easily refreshed.
iirc XP had a right-click/refresh thumb facility, but even without that, it was simple to delete the thumbs.db for that individual folder and regenerate a cache for just those few photos.
This Vista/7 technique is hopeless. There's no way to refresh an individual bad thumb, and because the cache for every single image ever viewed on the PC is stored in a single (annoying) location, one bad thumb in the cache can only be fixed by deleting thousands and then laboriously recreating the cache by opening every image folder individually and scrolling through all of them.
That's why I want to disable the cache, and just view thumbnails by having the system create them dynamically and not save them anywhere.
Terry, are there any other files in this folder besides the thumbnail caches?
I'd check but my Windows motherboard is in the shop, a power surge fried it this week.

If not, then the easiest way of pulling this off would be to just modify the filesystem permissions for this folder (properties | permissions). I'd remove the system privileges entirely, and make it read-only for whomever else has read/write permissions (your own account included).
I think you've cracked it CG.
Did a disk cleanup, set the folder to remove all permissions but read, went into Ubu to delete the cache files, rebooted W7, scanned a few image folders, ran DMThumbs (a thumbnail scanner app), and disk cleanup, and neither can find any cache.
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Neat, dang Windows has to give itself permission to do everything when its not needed....
The mystery deepens.
I have no thumbnail cache in my W7 user folders
I have no thumbs.db files in my picture folders.
If I "disk cleanup", Windows doesn't include thumbnails in the list of junk.
Therefore there should be no stored thumbnails, and they should be created dynamically.

So how come, when I look in my "cats" folder, I find thumbs from the original slide and negative scans, of images which have long since been reversed, cropped, processed and saved.

There should be no way the system knows that these images ever looked any different to the way they are now stored, but somehow it's still keeping a cache of these original scans, and nothing I do can show them the way they should look. !


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Hey Terry, in....

C:\Users\Mahmoud Al-Qudsi\AppData\Local\

IconCache.db, does that have anything to do with anything?
iirc from when I was digging around, that's a cache for the desktop and taskbar icons, nothing to do with picture files.
They still haven't fixed this in W8. Altering the Group Policy to prevent caching has absolutely no effect.
However the CG solution, remove write permission from everything still works. No more annoying thumbnail clutter on my C disk.
Those negative cat thumbnails are still there though, even on a system installed long after they were scanned in that state, so the only explanation for that must be that the jpg file has stored its own thumbnail in the metadata, and Windows uses that rather than generate its own.
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It *should* be possible to install Windows to an exFAT-formatted disk. That will eliminate all permissions-related issues, though it means you can't secure your accounts' files from being accessed by other accounts on the same PC (which is a non-issue in your case). Heck, I believe you can convert a NTFS partition to exFAT without formatting, though I'd test that in a virtual machine first.

Just a thought...
It would solve the problem of having to reauthorize myself to my own data each time I switch OS, but it sounds like it would make the caching problem worse. If there were no permisssions then there would be nothing to prevent Windows from continuing to cache despite the group policy being set to prevent it, or am I missing something ?
Ah, right. It's been so long since I read this thread! I got your two issues conflated - you're right, of course, the two solutions are mutually exclusive!
If you noticed Peter, I'm a poster in that link you included.
That's the point. The group policy is ignored completely. The thumbs get created regardless of how you set the registry or GP. Only using CG's fiddle works.
I didn't notice Terry, sorry about that. That's very annoying I agree. I might look into CG's fix as I find my main OS - Vista, repeatedly needs cleaning out of rubbish or else I start getting those 'not enough space' type messages.


Well I'll certainly keep an eye on it anyway. At the moment mine is only around 5mb.

I find my main culprit is my movie copying software which makes a complete backup every time, that's pretty drastic especially when it comes to Blu-rays.

I have to keep clearing that out.
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