While the team does who knows what with this problem, I want to remind all about several existing free scripts (and everyone should use scripts, because suffering makes no sense) to solve this problem TODAY:
1. https://github.com/dumbm1/ai_scripts/blob/master/ord/fastRelink/fast_relink.jsx by Marat Shagiev
2. https://community.adobe.com/t5/illustrator-discussions/relink-all-selected/td-p/9332967 by Carlos Canto and the community

For the convenience, I attach these as .txt here, since UserVoice has a strict policy about scripts in attachments.
You need to rename them to .jsx.

You don’t have to install them into Scripts folder even to access form File > Scripts even (but this would allow you to make an action with this script inside). you can just keep them where you want them and drag-n-drop them into Ai window when needed.
One of them should work. Just select images, run the script, pick one image and get all selected links replaced with this chosen image at once.

The solution of RV999 doesn't work if you need to replace an image with a different name and which is repeated for example 20 times within the illustrator file.

InDesign has an option to do this much easier but the developers of Illustrator are busy with stupid features and not with core functionality of the program, so this is the only work-around we have.. so here it is:

Best practices wen you start a new .ai file with links: Create first a v1 mother-folder, in it a WORK folder and in the WORK folder make a Links folder, don’t re-name it anything else. In the WORK folder you create a v1.ai file and link the images into the Links folder IN THAT WORK folder. If you want to link any image into that .ai file ALWAYS first copy the image into the Links folder and THEN place it into the .ai. This is important for your future sanity, trust me.

Now you want to make changes but keep the v1 version intact in case you need to come back to it: Make a v2 mother-folder, in it create a WORK folder. Then copy the v1.ai file in the WORK folder, rename it v2.ai but you will notice that the links are still connected to the v1 folder!!

How to make sure the links in the v2 search all at once in the v1 Links folder? You can re-link each manually but that is crazy time-consuming. If you try to just copy the Links folder from v1 to v2 Illu doesn’t automatically look there, it still looks in the old v1 folder! So how do you replace all the links at once?

So: Open the v2.ai
Open the v1 WORK folder and MOVE (not copy!) the whole (v1) Links folder to the v2 WORK folder
In the v2.ai that you have open in the background Illu will say it lost its links.
Click Yes>Replace and now you have an option to look in a new folder (check the little checkbox at the bottom ”search for missing links in this folder”), point it to the new location of the links in the v2 folder (manually navigate to the right folder or copy-paste the address of the correct folder in the top bar)

Important: COPY BACK the Links folder to the v1 WORK folder so the v1.ai still has its links intact!

Is there a better way to do this? So to re-link ALL the links to a specified folder?

This has truly added HOURS to my job working with packaging files with hundreds of individual files, many of which are repetitive. I now have to individually relink each of those files instead of being able to do it in one click like I could previously. I really don't understand why this feature has been removed. Does my monthly subscription mean nothing? ugh

Latest update – v 29.0.1 STILL hasn't fixed this issue. Why hasn't there been an honest update on this?

It's clear that Adobe doesn't care. They've never cared. As long as they keep getting their monthly subscription money, all our complaints are being tossed aside like trash.

Maybe this script will help untill it is solved.
When opening a file, click Ignore All
In the links panel, select the missing links to be replaced.
Click the Go to link button to select them on the artboard.
Download and run this script: https://shared-assets.adobe.com/link/476cf98b-768b-409f-6526-d6353e453ad8

This is absolutely ridiculous. I can't even begin to understand what's happening here. It's like the left hand is not just unaware of the right hand, but they’re both acting like they exist in entirely different realities. Adobe’s miscommunication clearly goes deeper than anyone thought possible. And honestly, I don’t blame the developers—they're just working with whatever nonsense they’re being fed—but management? They've completely lost the plot. Their priorities are so out of whack, it's a joke. I'm not using Illustrator to play around with some pointless AI drawing cute little birds. I need it to do my job, to actually reduce the mind-numbing monotony of tedious tasks, not add to it with unnecessary fluff. It’s like they’ve forgotten that this is supposed to be a professional tool, not a toy for showing off whatever half-baked AI features they think will impress people

Our prepress department just downloaded the newest version of Illustrator and the "Apply to all" option for relinking images when the linked filename has changed, isn't there anymore. We have to relink each instance of the file over and over, sometimes up to 75 times! We really need this function back! This is slowing our workflow down tremendously. Please bring "Apply to all" option back!

I just downloaded the newest update –V29. The requested function has still not been returned. I am trying to be understanding, but, what is the point of this? New features are cool and all & I clearly see Adobe pushing the AI features, but why aren't you returning functionality of link replacement?

I work in a flexo / digital printing company where we step up multiple 1-up master files to a die where for example it may be 6 across 13 around on a 12" die, meaning we have the choice it re-stepping it (and possibly mis-step due to a typo or basic human error) or relink each instance individually...

Illustrator used to be able to be tricked with a folder rename, redirect to the new Master folder and 'Apply to all'. Can't now.

Illustrator used to be able to select multiple images and replace them one after each other. Now it will only do one, then you select the next and replace that, then the next, etc, etc

I'm all for new features, but we've had very handy ones removed, then after protest, a mildly ok one replace them, why not just increase functionality of what was already there and unify it into a fully functional 'Replace Image' pane?

Adobe seems to be all for glitzy bells and whistles whilst removing core functional substance

Have you tried any workarounds? Perhaps there's a script or extension that can help automate the process.

Options displayed in 29.1.0.2 were not displayed in 29.1.0.46.

Beta 29.1 46
MacOS 13.6.9

No such feature found

Please stop using this method and return to "apply to all" as soon as possible.

Are you testing your own code before asking everyone to download the latest Beta version? All of the comments have been telling you the same thing for months now. You should create a file in Illustrator with 50 instances of the same link, then pretend you want to *replace* all of those (not "missing") links with an entirely different link. Can you replace all of them at once? That's what we need.

Just tested 29.1 40 and I opened a document that had several of the same link placed. I selected them. went to relink. and there was no options to replace all.. I had to still select the link multiple times.. as the popup re-appeared. is version 29.1 40 newer or older then 29.1.0.2
maybe im missing something.

GONE (IN BETA) 29.1.40

It didn't seem to be working as intended when I tried it on friday 9/20. I checked the "all instances" button but it still made me relink them all individually. Honestly, it's kinda hilarious that you guys could ***** this up this badly.

Bağlı dosyaları yüklerken
değiştir seçeneğinin tüm dosyalar için olması zaman kazandırıyor.

The new way to replace doesn't work correctly. Like Egor said it only works correctly when you select the files that need replacing, but even that doesn't work fully.

We keep a file saved with 10 files with a broken link, so when we open the file it opens the dialog box for replacing or ignoring the links. No matter which of the 3 replace options I choose it will still ask me for each individual file how to handle it. This is not efficient.