EPS file from older version of illustrator now not editable

[JeannieLD]

I created a number of EPS files in 2017 using a prior version of Illustrator. Each figure/file (these are maps and graphs) has multiple layers, fonts, polylines, symbols, colors, etc, and I had no trouble editing previously. After a couple of years, and after updating my Illustrator version, I went to open one and it is just an image. What was 32Mb eps file editable and created in Illustrator is now just a useless 4Mb flat image. Any ideas how to fix this? What have I done wrong? 

[Monika Gause]

Do you still remember what kind of EPS you saved?

[JeannieLD]

I'm embarassed to say I don't know what this means. An Illustrator-EPS? It has only been created and edited in Illustrator (though a previous version). 

[Monika Gause]

Did you save as Illustrator EPS 3? Or 8? Or higher? Did you flatten transparency (in case there was transparency)?

Apart from that: where did you store the file? Did you send it via e-mail? Did you save directly to a network drive or USB?

[JeannieLD]

Thanks Monika,

The files are on my Box drive. I may have moved them from one sub-folder to another within a parent folder - but nothing more. 

[JeannieLD]

EPS 8 sounds correct, and yes, I believe I flattened transparency. 

[Monika Gause · Accepted solution]

Saving down to EPS 8 got rid of editability unfortunately. Saving as older EPS should only happen on top of a current AI file.

This is how EPS works: https://www.vektorgarten.de/eps-file-format-zombie.html

It's not a native file format of Illustrator.