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CM87 Preview Handlers

Page no: CM87
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Problems Windows Preview



One major problem for Portable software is that are no so-called Thumbnails:
Preview of files inside Windows Explorer.

In the pure “USB installation” of portable software one cannot write into the registry.

Background on Microsoft

In our extended view of portable, we would like run scripts that register the thumbnails with registry DLL.


What kind of file types can show thumbnails:

Any image




Details on PDF Preview

Source: sumatrapdfreader

No thumbnails for the portable version?

Yes, thumbnails only work if you install Sumatra (and select thumbnail creation during install step using ‘Options’ button).

In Windows, generating thumbnails works by registering a dll that Windows will call to generate a thumbnail for a given file type.

Only installable version of Sumatra provides this dll, for 2 reasons.

1. Portable version ships as a single executable, for convenience. There’s no room for shipping a dll.

2. The idea behind portable apps is that it doesn’t leave a trace on your system. You can fully remove it by removing the executable file.

To register thumbnail provider we need to modify registry and we can’t allow for the dll to be just deleted by the user without first unregistering it with Windows.

As to changing the icon: there are many programs that allow editing resources inside a Windows program and an icon is just one kind of a resource.

You could create a new icon and use one of those programs to replace the icon inside SumatraPDF.exe.

Download: Sumatra Portable Version for WIndows Preview Handler

Download: FOX PDF as Windows Previewer

Sumatra: Is Windows Preview/Thumbnail for PDF
Sumatra: Is Windows Preview/Thumbnail for PDF

- Click to enlarge


View Ccleaner

CCleaner Register Thumbnails

With CCleaner is also able to register thumbnails for portable version.

see under context menu

CCleaner Register Thumbnails
CCleaner Register Thumbnails

- Click to enlarge

Register Applications

See details in Export, Import Registry Page


Registry export solutions

Export Registry from one computer

Save as script

Load script on other computer



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