Does relaunching Illustrator help? Restarting the computer?
Do you have something RAM0intesive running on your Mac at that moment?

Have tried to reboot illustrator many times and reopen my files but it still states can't finish previewing and just shown the outline mode. It crashes when I do my work too
Please help to fix thanks

Stuck in Outline mode, there is a pop-up window that comes up saying "can't finish previewing. Could not complete the requested operation."

I try to do something in Illustrator and that pop-up comes up and I can't do anything to fix it. This is making it impossible to get work done as I'm just stuck in outline mode, if I hit Command-Y nothing happens but the pop-up.

Goes into Outline view.. Preview mode works when I click the eyeball icon for one of the layers (i.e. turn it off). Using iMac, Big Sur 11.6, AI 26.0.1, 16gb RAM.

This is also happening on the M1 Macs - Enough memory (RAM)

May 2021, I have to stop working for today, AI switches to outline mode with the same error message op described, and other stuff I did today made it crash, I don't know what's going on here but this must be the latest update I installed (version 25.2.3). Very annoying.

Version 25.2.3 And it has not yet been solved. It is impossible to do my work.

I have cc2020, and this still happened.

I applied a pattern to a stroke by accident and received this error. I'm using v25.0.1 on a PC with 16 gb RAM and a dedicated graphics card.

I applied a pattern to a stroke by accident and received this error. I'm using v25.0.1 on a PC with 16 gb RAM and a dedicated graphics card.

I get the "Cannot Finish Previewing. Could Not Complete The Requested Operation" pop-up message and my view goes to Outline Mode when I use the Pencil Tool with a Gradient Fill. I need to save & close the file, reopen it in Outline Mode and then select GPU Preview to see the accurate preview again. Happens every time. I can turn fills off in the Pencil prefs, but that sort of defeats the purpose. Driving me nuts! Please advise.

On mac mini with 64GB w/ a Raedon RX 580 8GB eGPU

Hello from 2020. Not fixed.

I had the same issue on my Apple Macbook Pro (OS Mojave) when using any version of Adobe Illustrator. I went onto Adobe help centre and did an online chat with an agent who logged in remotely to my computer and fixed some files and renamed and deleted a few things, been working ok since.

24.2.2 version crashes automatically. please help

Illustrator crashes while opening other files automatically. Also many times getting can't finish preview while working on linked PDF file only. see attachment, please provide solution.

Same here.

I'm drawing a line with the pencil tool (9 points) over a locked photograph, and I'm getting this message.

Concerning because it's a basic, basic, basic exercise for my sophomore design students.

New MacBook Pro, Catalina 10.15.6, Illustrator 24.2.1

Please Fix!

Please update Adobe! Illustrator crashes every day... Also sometimes it will not let me switch between documents. Even though the indicator says that I switched between files, the screen remains the same.

I lost a surface pattern design on 24.2.1 also, as well as spent all of July 4 frustrated and mad as **** at the constant crashing and rebooting that, in the end, did me no good.

This is happening again with the 24.2.1

agree... mine crashed 2 times today and lost 30-40 min of work