Globally Unique Identifier

Globally Unique Identifier is a genious thing when you need a globally unique identifier! They are not as brilliant when they are used everywhere you would need a human-readable name, because of laziness.

If you've ever been troubleshooting a Windows program, and you have if you are reading this blog, you are fully aware of the frustration you feel trying to find the associated file from a class identifier in the registry or when figuring out which program C:\Windows\Installer\{136688F1-EF42-414E-92D6-BFF4D25EE688}\ARPPRODUCTICON.exe belongs to.

Usually you just copy the GUID into the clipboard and paste it into an appropriate search box. Isn't obvious that {25336920-03F9-11cf-8FD0-00AA00686F13} is the CLSID for "Browse in place"?

It doesn't help then, at all, that there are two ways of storing the GUID, either normally or compressed. And by "compressed" I mean "not really compressed, just a little different to annoy people and make their life harder".

How to convert between a standard and a compressed GUID:

Have you seen anything dumber than this, lately?

Also note that the "Browse in place" GUID, usually found under keys such as HKCR\htmlfile or HKCR\jpegfile, have two lowercase letters for no reason. It's likely true on your Windows too. To be truly globally unique, GUIDs should be generated by an algorithm standardized by ISO, IEC or someone with power to standardize. I am not sure, but I doubt the algorithm is inconsistent with upper and lower case.

Sometimes it is obvious the GUID is not random, as in the case with Microsoft Office;

The product code for Office consists of it's version and language and such, ending in "0FF1CE" as Microsoft describes here. My Office 2016 Pro has a GUID of  {90160000-0011-0000-0000-0000000FF1CE}.

Older Java clients had class IDs starting with "CAFE"; {CAFEEFAC-0013-0000-0003-ABCDEFFEDCBA}, or maybe it should read "Café fuck", because that is how I read it.

Finding the product code for an msi install is trivial when the program is already installed, but often you would like to avoid littering your computer, even your virtual one, with garbage unless you really have to.

I wrote a tool to list the product codes of all msi files in a folder, and also put them in the clipboard for easy pasting into your uninstall-script. Download it here.

If you don't dare to download unknown programs and run them on your computer you are not an application deployer.