Thanks - this issue has been resolved after I re-installed DWG TrueView (see message 18 above)
After struggling with this issue and looking for a solution, I discovered the system variable "RASTERPREVIEW" which according to the AutoCAD 2010 help file, "controls whether BMP preview images are saved with the drawing."
When "RASTERPREVIEW" is set to "0" and the drawing is saved, the thumbnail is NOT displayed in either Windows Explorer or the AutoCAD Select File (Open) dialog. Selecting the file does NOT display the preview.
When "RASTERPREVIEW" is set to "1" and the drawing is saved, the thumbnail IS displayed in both Windows Explorer and the AutoCAD Select File (Open) dialog. Selecting the file in this case DOES display the preview.
The result of toggling the RASTERPREVIEW variable is nearly instantaneous on my machine. Turning it on (1) makes the thumbnail show up. Turning it off replaces the thumbnail with the application icon.
See attached screenshot of the Select File dialog.
I'm still working with AutoCAD 2010 so this may or may not be a solution for everyone.
What setting or variable does this? Our Open Preview is missing too. (using 2013 products) If I set the profile to the original / default <<unnamed>> then I get the preview pane during the open dialog box. Otherwise I don't. I remember (ages ago) some utility that compared settings in drawings or profiles.... anyone remember what that is?
To avoid loosing your preview again don't use the DXFIN command. Insert DXF files using the open dialogue box and select file type. I don't know if there is a variable to fix this.
This worked for me!
- Check that next key in the registry is setup = 1:
(Of course some paths were a bit different. The thing to look for is your is the Profile)
Seems there should be a variable or setting of some sort in AutoCAD for this.