I'm also having this, and it's really random – like on a file, it'll replace fonts in the document with another font also in the document. Sometimes it's like Times or Myriad.

It's really mindbogglingly random. It seems to happen when a file has missing fonts at all (like this file, the printers dieline had missing fonts), and then it randomly replaces stuff

I still see the same issue. I’m attaching the previously saved JPG in the same artboard for comparison. The error seems to happen after Find and Replace Font or when using Select > Same > Font Family/Style, but I’m not sure if that’s the exact cause. This is not a missing font error — all fonts are installed and active. The file saves and exports JPGs fine, but when reopening the .ai file the fonts change.

This fix is included in Illustrator v29.8.2. If you reopen files that were not saved while the font change issue was present, the problem should no longer occur. Please let us know if you continue to experience the issue in v29.8.2.

I think because the problem is intermittent, its not a fair test to just open up an unaltered document

Hello. We’d like to ask everyone here to test this in the latest Beta build (30.0.0.48 or later).
Please reopen an original .ai file (saved before the fonts were unintentionally changed) and let us know in the comments whether the issue is resolved or still occurs.

When I open the files which had the fonts changed in 30.0.72 the issue still occurs - is it the apple silicon version? I wondered if the issue might be with silicon/intel?

good news
I have downloaded illustrator beta 29.9 and 30.0
The problem seems to have finally been resolved with both versions

with all version of illustrator closed
you can right clic on the file and choose open with illustrator 29.8.1
(if illustrator is alredy open the problem does not occur)
save with a new name
when you reopen the new file the fonts are switched permanently
is not a visual problem they are changed randomly using other font used previously in the original file
I attach the test file resaved from my mac

The one that opens for me when a file gets double-clicked is Beta, because it was installed last :/ it’s something Windows does and the only way to change it it to reinstall GA build. When I try to do these steps — still doesn’t happen for me!
Can you at least show or tell what fonts do you get? do the names change or do they change only visually?

you have to double clic the file with illustrator closed
if illustrator is alredy open you don't see the problem

1 quit illustrator
2 double clic the file (don't worry opening fonts)
3 save with new name
4 reopen the file

Alas, Marco, can’t reproduce it.
This is what tried:
1. Opened the file with 29.8.1 and installed the missing fonts
2. Saved it under a new name(with no font embedding), closed the document
3. Double-clicked the file
The fonts are the same: Espiritu Condensed and Mislab Std Compact Demi
What do you get when these do change? Or do they change only visually, and the names stay the same?

hi all
I have something new about this issue
I have a file made with Illustrator 29.2
if I open the file on my mac with 29.8.1 and save with new name it is all ok 
but
if I have Illustrator closed and double clic the file that starts Illustrator and save with a new name
after reopen the new file the fonts are changed
 
I attach the file so you can try if you have the same result
I hope this can help to solve the problem

Not sure if this is related to the same bug, but... I noticed that, when reducing the size of a text box to less than the amount of text there is, the fonts simply invert between bold and regular on display, even if the fonts still register the correct one on the character menu. See the video attached. This is getting ridiculous!

sometimes when I open a file I have already worked on, fonts go missing even though I used them before closing the file.

Is there any update/bug fix /Work-around for this issue. We're using version 29.6.1 and this issue still persists. Like the other users we tried reverting back to 29.4 and it didn't resolve the issue.

Same issue with FONTS changing.. and also having this PLUG issue. and nothing seems to work to fix it. Version 29.7.1

Hi, can you share a file which shows the issue?

In the latest version of Adobe Illustrator, I often experience random font substitution issues when opening older files. The fonts are properly installed in my system, but Illustrator does not recognize them correctly.

For example, if I copy the same AI file 10 times and open each copy, Illustrator displays different random font substitutions each time. However, when I open the same files in an older version of Illustrator, the fonts display correctly without any issues.

This indicates that the problem is not caused by missing fonts, but rather by how the new Illustrator version handles font data in older documents.

Steps to Reproduce:
– Create a file in an older version of Illustrator with specific fonts.
— Open the same file in the latest Illustrator. Fonts are shown incorrectly or substituted, even though they are installed.
— Copy the same file multiple times and open each copy → the substitutions are inconsistent and random.

Expected Result:
Illustrator should recognize and apply the installed fonts correctly, just like in the older versions.

Actual Result:
Illustrator randomly replaces fonts with incorrect ones, even though the correct fonts are installed and available.

System Info:
OS: Microsoft Windows 11 Home
Illustrator version: Illustrator (29.7.1)
Fonts: Various fonts are affected, not limited to a specific family. For example: Montserrat, Anja Eliane, Questrial, Poppins, and many others. The issue occurs randomly with different fonts each time, even though they are all properly installed in the system.

I am also running the current version of Illustrator 29.7.1 and have just now had the issue reoccur

I've reopened the two files that have been affected by font swapping, and opening them in Beta 29.9 doesn't resolve this