Finding Type/Creator Tags in Old Mac Document Files

I saved old files from my Mac Plus days and I’d like to open them with applications running under Monterey.

Of course, in the old days files didn’t need extensions and I didn’t include them in file names. Now many of these these files without extensions are displayed as “exec” files in the Finder and double clicking on them is of no value. Some files say “ Microsoft Word 1.x-5.x document” in the Kind field of a Get Info window, but most just say “Document” and give no indication what application produced them.

If I open the files in BBEdit, sometimes I get a hint of the application that created them. For example, some files have the plain text “SIT” near the beginning. Sure enough, adding a file extension of .sit allows me to open these archives with BetterZip.

Can anyone think of a way to figure out what application can open an old Mac document file? I was thinking that the best way of identifying the associated application for an old document file would be to extract the Type/Creator tags.

Does anyone know how to extract Type/Creator tags with an app that runs on Monterey?

Thank you.

Both PathFinder (CocoaTech.com) and A Better Finder Attributes (PublicSpace.net) can work with type and creator codes for old files. It’s up to the user to research what apps are associated with what codes, but the codes themselves are available. I’ve found that the two are best used in conjunction with each other, as each is suitable for different tasks.

Libre Office is my can-opener. Especially for word processing files, it pulls the text and maybe some formatting for almost any word-processing file back to MacWrite (including the inscrutable WriteNow). It’s donationware, so give it a whirl .

There is no need to play with type and creator codes. Just open the program and then open the file in question. It will give you something to play with more often than not.

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Turns out that I already have PathFinder as a result of a software bundle I bought in December. Now I have a use for it!

Not only does it exhume the Creator tag, it even displays the application icon occasionally.

Thank you.

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In my experience, this is a problem that appeared after I upgraded from Mojave (10.14) to Monterey (12). In Mojave, I would get sensible file types and icons for my older files with type/creator codes and no extensions. But now, even when the Mac understands the document type based on the type/creator codes, it displays the wrong icon. And even then, it displays a different incorrect icon for different files, with seemingly no reason:

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But to answer your question about how to access type/creator codes, Apple actually provides a command line tool for this called GetFileInfo:

> GetFileInfo Initial\ letter\ to\ Prof\ Smyth
file: "/Users/me/Documents/Correspondence/Letters/Initial letter to Prof Smyth"
type: "WPD3"
creator: "WPC2"
attributes: avbstclInmedz
created: 05/18/2002 13:08:02
modified: 05/18/2002 13:08:02

You can get just the type code or just the creator code:

> GetFileInfo -t Initial\ letter\ to\ Prof\ Smyth
"WPD3"
> GetFileInfo -c Initial\ letter\ to\ Prof\ Smyth
"WPC2"

So it would be relatively simple to create a script (e.g. in AppleScript) that you could drop a file or files on, and it would extract the type & creator codes, look up the document type associated with them, and append the appropriate extension to the file.

You would have to manually create this lookup table, and there is no ‘master list’ to get the type/creator codes from. But there are some lists already on the web that most likely cover any file you’re likely to come across. And any files you have not on these lists, you could do a search and find out what they are. (As an aside, a lot of the creator codes can be guessed from the letters used, but some are ‘obvious’ only because they became well known, like BOBO for ClarisWorks/AppleWorks and R*ch for BBEdit.)

[Pythonmac-SIG] Discovering file type
Mac Creator and File Type codes

(As a final aside, Apple also provides the corresponding SetFile command line utility, so creating reverse script – assigning type/creator codes based on filename extensions – would also be possible.)

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