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On Windows Server 2012 there's a file association for ".pdf" with a registry entry in HKEY_CLASSES_ROOT, however when we try to open a ".pdf" file a message explains: "Windows can't open this type of file (.pdf) Try to find an App...". It looks
like a bug, if the Windows Reader App isn't installed we should not have a ".pdf" file association?
The file association for ".pdf" just lista common registry entry in register editor. The .pdf file could be opened or not depends on the program installed on your server NOT just only the registry entry association.
Just like you mentioned, you could open the .pdf file with a program on your PC or Try to find an App in Windows Store.
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