If you're reading this, you might have been told by SumatraPDF that you have a corrupted installation.

How can that happen?

SumatraPDF comes in two flavors: a portable version and an installer.

A portable version is a self-contained executable and cannot be corrupted.

An installer needs to be run to be properly installed. Part of it is extracting libmupdf.dll library needed by installable flavor.

You cannot just rename the installer and run it.

There are 2 possible problem:

• libmupdf.dll is missing
• libmupdf.dll is there but its version doesn't match the version of SumatraPDF.exe

How to solve the problem?

If you want to place SumatraPDF in any location, under any name, use the self-contained portable flavor.

If you insist on using the installable version, just install it. The installer will run if it has -install in the name of the .exe (which it will if you download official build).

If you rename the .exe, you can force running the installer with -install option.

Alternatively, you can extract libmupdf.dll and all other files with -x option.