Solving Mac File Amnesia with Type & Creator Codes

I recently received a request for help from a research group who had an old Macintosh file they couldn’t open. The file was created in the late 1980s in a statistical research program, but they couldn’t extract the contents no matter what they tried. The data was not stored in text format, and the file had developed a case of amnesia: it didn’t know what it was, and no software could recognize it.

Old Mac files contain two embedded strings, called Type and Creator codes, which tell the Mac OS what kind of file it is and which program was used to create it. An equivalent kind of file type identification is used in most operating systems (including Mac OS X) in the form of a three character extension after the filename, e.g., filename.txt. This embedded data was missing on my client’s file, which is not uncommon when files have been copied across multiple disks and platforms over many years.

My client thought the file was originally created in a program called StatView. I found an archived copy of the software online at the Macintosh Garden (a great resource for Mac Abandonware), and tried to open the file. No go. I also tried some other statistics programs I have around for good measure, but nothing worked.

Next I launched Statview again and created a couple of test files, in both the “StatView4.1” and “old StatView” formats. This creates samples which contain the correct type/creator codes. Using File Buddy – another venerable old utility – I applied these codes to copies of the original file, then tried to open the copies. The file tagged as “old StatView” did the trick and opened no problem. Sweet. From there it was easy to export the data in text format (TSV), then import into Excel for use with modern computers.

For a situation like this it helps to have some guess as to the original software used. Creating sample files in various formats is a helpful way to apply educated guesses about missing type/creator codes to other amnesiac files – assuming you can find a copy of the software in the first place.

My client was thrilled to hear the news, they’d been working on this file for some time and had already gone down several dead ends. I asked what the data was for, and was told the following:

The data is from a European researcher. I am conducting what is called a “systematic review” which involves looking at every piece of data in a given area, in this case, vegetarian diets and weight loss. If I do not incorporate all the data (even those kept in old software in a foreign language) then my findings would not be considered complete.

You’ve saved science!

Nice. It’s not every day one gets to save science. Vintage Macs to the rescue!

2 responses to “Solving Mac File Amnesia with Type & Creator Codes”

  1. Dan Miller says:

    It was great to see The Macintosh Picasso Dealer Sign on your site. I’ve had one since about 1991, which I purchased at a flea market in Cupertino. I have rarely seen on on eBay or elsewhere, and have no idea what value they may have. Without asking what you may have paid, could you speculate on the range of asking prices that you have seen recently? Mine is in quite nice condition and the lamp works fine. Thanks from a Mac user since 1986, and still going.

    • Adam Rosen says:

      Dan, the signs are currently selling for between $500-750 on eBay, from what I’ve seen in the past year. They were going for about $1k a couple of years ago, and I suspect they will increase again in value over time.

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