Changing units doesn't change anything.

Working in pixels but values show millimetres.

This BUG (not an idea) comes and goes with each iteration.

This is meant to be professional software—why are basic things like measurement and colour consistency so useless?!

Dear Raj Nagi, this will not solve the problem.

Once units are changed in preferences they need to stay as preferred... (why is it a preference then ?)
Automatically switching back to points for some mysterious reason is pretty annoying.

Right-click on the ruler Bar. Select units. This will sort out your problem :)

I am experiencing the exact problem using Illustrator 24.0. It is very annoying to need to reset the increment on every new file

Yes, this isn't great. It never used to be like this, and then Illustrator decided to change this behaviour. Surely the presets can have whatever they like in their document, but when you make a NEW one based on that preset, it should translate the internal document units to your preferences value, e.g.
Letter 612pt x 792 pt => open as new => Letter 8.5" x 11"
A4 841.89pt x 595.27pt (wtf?) => open as new => A4 210mm x 297mm

Depending on if you are setup as mm or inches.
PS. USA is the only metric hold-out for consumers - most of the industries have already switched or have accelerated their switch to metric after the Hubble Space Telescope metric/imperial disaster for NASA. LOL!

I am also frustrated with not being able to set my own personal unit preferences in AI. This absolutely used to work - both under CC and CS - not sure why the developers felt it had to change. It isn't as if CC is an open source/free package with no support. We all pay good money for this suite of applications and should expect basic functionality such as having our personal configuration preferences remain stable from document to document and session to session WITHOUT having to jump through hoops or using some "obscure trick" that someone stumbled upon that happened to work.

right-click on the ruler. Select units.

Very annoying and this is now happening in InDesign as well! Both Illustrator and InDesign used to be fine regarding these size preferences and you only had to set them once.
Please can Adobe fix this problem. Surely it can't be that hard?

Its every time I create a new document, and sometimes when I open other peoples work.
I only want to work in inches. Nothing else. Ever.
Don't get me wrong, I like MM, but my industry doesn't work in MM. It works in inches.

Set illustrator to the metrics you want. Close. Open illustrator. Create new file. Copy art from old file in new file fixes the problem for me.

This is happening again for me in v23.03.04. Please fix.

Why would you make documents default to pts? Has anyone EVER in the history of mankind had someone say "Hey Johnny, can you make me a graphic 432 pts by 597 pts?". Do they sell the points rulers at Office Depot now? just checking ;)

most annoying thing. Some documents I have open will be in inches (my preference as a product designer) and others will be in points. Even though when i open my preferences, it says general: inches. but surely, my transform tool stays in points. I can type my inch dimension with a " and it will convert it to points. so frustrating. this has been happening for years and finally i cannot take it anymore

Setting up a new document with inches in preferences then leaves transform in points. How do I change that?

... and yet here you are David wasting yet more time making your point

'surely pixels is the most common', maybe in your huge pond

It is MUCH less likely that many users will want to have multiple options for measurement units. Preferences should establish what a user generally want. So once a user has set Pixels to the unit of measurement that should be the default. Then if another unit is set for a document - that single document uses that unit and follow the document. I don't think Points is very commonly used at all. it should not be the default. surely pixels is the most common. It is so annoyingly wasteful of time that this many users have taken the time to make a comment. Consider that it might be 1% of people who take the time.

Absolutely fix this pt/vs inches issue. I'm dealing with it right now as a product designer. I can't get anything to work measurement wise. Also...Please work with apple so your software doesn't crash the OS every 10 minutes...both in AI and PSD.

BTW the above tip does work on Adobe cc 2019 with a doc open. Save pref units as millimeters/MM. then re-open prefs and save units as inches. Thanks Jude Wood!

please fix this bug!!! the preferences and/or units in the artboard set up should change the ruler and all units in the document. I want inches -- i work at a publication that uses inches!!!!!

even if i open a doc created in points, when I change the artboard and/OR preferences units to inches, the document should CHANGE!!!! for me the user, not you the coder.

Changing the units in Preferences won't change anything if your document is set up in another unit of measurement. It will work when creating new files but if you're working with a file that was created by someone else or before you switched your preferences, it will revert back to the native document settings. If this happens, open up the file that you want to change the units of measurement in and go to File > Document Setup, change "Units" to your preference, hit "OK" and then save the file before closing. It looks like document setup overrides preferences, which makes sense. Hope this helps everyone.