My Rhino 7 no longer generates thumbnails for the files saved after the end of 2024. It may be related to updating Rhino 7 to Version SR38 or Rhino 8 on 26th December. My files prior 26th December have thumbnails. Is there any known fix for this? 
Hi Bobi,
Files created with my Rhino 7 SR38 and Rhino 8, on a local drive, under Windows 10 22H2, show thumbnails. What version of Windows are you running?
Regards
Jeremy
Using OneDrive?
Hi @jeremy5 ! I use Windows 10 Version 22H2 for x64-based Systems (KB5050081) and Rhino 7 Version 7 SR38 (7.38.24338.17001, 2024-12-03) Commercial. I updated both, my Rhino 7 and Rhino 8 Evaluation in December and since then the files saved with Rhino 7 no longer have a thumbnailā¦
I donāt use OneDrive, just saving on my local SSD and two HDDs. No matter the drive, there are no thumbnails.
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a) If you open one of the files without a thumbnail and then save it, does that make a thumbnail appear in Explorer in a medium-sized icons or larger view? If not, does hitting the refresh option for the view make a difference?
b) If you open one of the files with a thumbnail and then save it, does that make the thumbnail disappear from explorer? If not, does hitting the refresh option for the view make a difference?
The thumbnails of any files older than 26th December 2024 are visible, but newer ones are not shown, no matter which settings in Windows Explorer I use.
When I open an old 3dm file which has a thumbnail and then save it, the thumbnail disappears. The bug seemingly is caused by the Rhinoā¦ However, the ā3dmbakā file has a thumbnail when I change the file type from ā3dmbakā to ā3dmā.
If I manually change the file extension from ā3dmā to ā3dmbakā and then return it to the original file type ā3dmā, it does not have a thumbnail.
Here is a new Rhino 7 file which shows a thumbnail on my machines in both Windows 10 and 11.
If you download it to a folder where you normally keep Rhino files and view that folder in Explorer (before opening it in Rhino!) do you see the thumbnail?
ThumbTest.3dm (35.0 KB)
(The file only contains a single cube)
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Thank you for this test 3dm file! Looks like itās a Windows-related thing, because your file does no have a thumbnail when I save it in the same folder where my older 3dm files from last year have a thumbnail. Interestingā¦ Maybe something with the file association?
I donāt think it is the file association - I have mine set to a separate program which then hands the file off to Rhino, but as you see I get the thumbnail.
Windows will use a file handler supplied by McNeel to display the thumbnail. That handler will be lined to Windows via a registry entry. It may be that a Windows update broke that association (you could check your Windows Update history to see if one was installed around that time).
If that is the problem, then I speculate that running the installation repair option on Rhino 7 may reinstate it. Someone from McNeel can doubtless be more definitive about thisā¦
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I just updated Windows to the optional preview version, but the 3dm thumbnails are still not fixed.
Trying to figure out how to refresh my Rhino 7ā¦
Savingfiles with Rhino 7 in safe mode (wireframe only) does not fix the issue either.
Hi @Rhino_Bulgaria,
Please try the following:
1.) Close all running copies of Windows Explorer.
2.) Bring up an administrative command prompt
3.) Navigate to the following folder:
C:\Program Files\Rhino 7\System
4.) Run the following from the command prompt:
regsvr32 RhinoHandlers.dll
Does this help?
ā Dale
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Hi @dale ! I tried that, but it returned the following message:
C:\WINDOWS\system32>regsrv32 RhinoHandlers.dll
āregsrv32ā is not recognized as an internal or external command,
operable program or batch file.
However, the good news is that I was able to fix the issue by doing a system restore to an earlier restore point from November. I lost some recent custom icons with macros, but at least I can see the thumbnails again.
Thank you all for your time in trying to helping me out! I appreciate your effort! 
Bobi, you mistyped it. Should be regsvr32, not regsrv32. Just in case you ever have to do this againā¦
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My bad. Anyway, I will keep this in mind if I face the same issue in the future.
does this work for Rhino8 @dale ? Iām getting no preview thumbnails at all, Windows 11 
Yes, did you try?
ā Dale
