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Prevent Thumbnail generation

Also by EldoS: CallbackDisk
Create virtual disks backed by memory or custom location, expose disk images as disks and more.
#20882
Posted: 07/25/2012 06:56:48
by Christopher Lenz (Basic support level)
Joined: 07/25/2012
Posts: 16

How can I prevent windows for generating thumbnails.
These files come via an external system and take a long time only for thumbnailing.

All files and folders are marked as Offline

Chris
#20883
Posted: 07/25/2012 08:13:12
by Volodymyr Zinin (EldoS Corp.)

There are several of similar questions have been already on these forum. Try to find them.
One of the options is to use the network type of mounting points (the flag CBFS_SYMLINK_NETWORK for the CallbackFileSystem.AddMountingPoint method). In this case the system minimizes getting of thumbnails because it thinks the drive is remote.
#20884
Posted: 07/25/2012 08:24:05
by Christopher Lenz (Basic support level)
Joined: 07/25/2012
Posts: 16

Quote
Vladimir Zinin wrote:
There are several of similar questions have been already on these forum. Try to find them.
One of the options is to use the network type of mounting points (the flag CBFS_SYMLINK_NETWORK for the CallbackFileSystem.AddMountingPoint method). In this case the system minimizes getting of thumbnails because it thinks the drive is remote.


I tried exactly this but if you focus a picture the thumbnail is generated
#20885
Posted: 07/25/2012 10:20:03
by Eugene Mayevski (EldoS Corp.)

Unfortunately there's no definite solution to this problem :(. One *possible* solution *probably* would be writing a shell extension which will disable thumbnail mode for viewing, but if the user has chosen a file in Explorer, then it's likely that the user wants to get some information about the file and thumbnail is legitimate in this case.


Sincerely yours
Eugene Mayevski
#31526
Posted: 11/26/2014 16:59:16
by Sergey Fetisov (Basic support level)
Joined: 11/12/2014
Posts: 1

Is there a way in ReadFiles to differentiate the calls being made from 'Windows Explorer' and say 'MS Paint'? That ways I can always serve thumbnails for Windows Explorer, and full file contents for others.

Another solution, can a Thumbs.db be used in this case, so that the Explorer uses the thumbnails from this cache, instead of giving a call for file content.
#31527
Posted: 11/26/2014 23:53:51
by Eugene Mayevski (EldoS Corp.)

Quote
Sergey Fetisov wrote:
Is there a way in ReadFiles to differentiate the calls being made from 'Windows Explorer' and say 'MS Paint'?


You can use GetOriginatorProcess*() method in a handler of OpenFile/CreateFile event, however the difficulty is that in OnReadFile there's no per-handle context. The reason is that reading is done note by the process, but by the cache manager, which later provides the data to multiple projects. Consequently...

Quote
Sergey Fetisov wrote:
That ways I can always serve thumbnails for Windows Explorer, and full file contents for others.


...no, you can't. The content served must be the same for every process that opens the file. This is because Windows cache (and CBFS' cache as well) hold only one copy of the data and metadata. You can't give different data to different processes.

Quote
Sergey Fetisov wrote:
Another solution, can a Thumbs.db be used in this case, so that the Explorer uses the thumbnails from this cache, instead of giving a call for file content.


We only heard of thumbs.db but never used it (and seems that no-one of our users did as well). If you do something with it, please let us know.


Sincerely yours
Eugene Mayevski
#32631
Posted: 03/15/2015 23:54:12
by Sungkun Choi (Standard support level)
Joined: 11/24/2009
Posts: 12

1. Mount with CBFS_SYMLINK_NETWORK options.
2. Add DWORD Name & Value to registry.
- Location : HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\Explorer
- Name : DisableThumbnailsOnNetworkFolders. Value : 1
Also by EldoS: SecureBlackbox
200+ components and classes for digital security, signing, encryption and secure networking.

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