Yes, the fix did solve it.
However I just need to say, that this problem should absolutely not be there, unless Steinberg was a completely lowly amateur one-guy-is-the-whole-company deal.
It is gravely infuriating to spend hours on such a problem, and I am mind-blown that Steinberg thinks that this is ok. How about Steinberg did some programming that could make it possible to install their software EVEN if you had some weird font in your system?
You must not ever use publishing appsā¦ Font issues have been ongoing since the dawn of time, welcome to your first one.
Go tell Adobe they need to redesign Photoshop or Illustrator to accommodate for a users corrupted fonts that can bring those apps down too.
Itās not their job to verify every random third party font file you installed was made to spec or even works properly. If some dev codes a crappy VST plugin that crashes DAWās left and right is that Steinbergās fault too?
maybe Iām not compressing the file correctly but this hasnāt worked as a fix for me. I open the finder app, shift+command+G then search library/fonts/ double click on the only file that appears then click the compress prompt. Any help?
Thank you. Fixed my problem. I opened font book, typed in the ārestoreā in the help bar and the option came up. clicked it, fixed.
Thank you for the feedback.
We have a help center article on this issue for those interested:
macOS: Steinberg Download Assistant does not start or shows a spinning wheel ā Steinberg Support
WHOA, NO - I do a lot of graphics art work, and I cannot risk problems with dead font links to my graphics programs. And I have a lot of fonts.
This solution does not work.
I D/Lād CP13 direct, I have my license number ready to enter. I was directed to the activation manager, but CP13 does not appear anywhere - not under all products or under not activated.
Iām tempted to reverse the charge because of āproduct does not operateā, if this isnāt solved.
OK, Steinberg, hereās how you fix the font issue, without having to remove / reinstall the fonts en masse:
Open the Font Book
Select All
Right Click āValidateā
Any that pop up with a red warning, remove with āRemoveā command. If you canāt remove them by clicking remove, then go into the System library, and click on the fonts folder, and delete from there.
Then, to be sure, close both font folders and re- open teh font application, repeat select all, and make sure the red flagged ones are gone.
If they are, you should be able to run the download assistant. Maybe restart, if not.
Thank you azureblue! I was nervous about messing around with my font book files, and your suggestion worked for me. Whew!
Youāre welcome - glad it worked for you, too. I hope I described the process clearly enough. I have a lot of saved graphics projects, and there would be havoc if the projects lost link to the fonts.
I cannot thank you enough for this; I have a lot of wacky fonts, as well, and this saved me 
Didnāt help, unfortunately. MacOs Sequoia, all fonts to default, no errors, and the installer still would give an error.
Iām using a Mac mini with the M4 chip running macOS 15.3.1, and I honestly think this persistent font conflict issue is a result of irresponsible coding. Even after passing all validation checks, the app still refuses to run. Uninstalling and reinstalling does absolutely nothing.
Itās unacceptable that users are expected to reset fonts and manually reinstall only the āapprovedā fonts every single time this happens. And to make things worse, trying to check for an update is deliberately made difficult.
This kind of repetitive frustration being forced onto the user is simply inexcusable. Itās clear that the development team needs to take this issue seriously and implement a real solution. We, as users, should not have to bear the burden of broken design choices.