Some ProRes 422 Video Preview Files lost on closing and re-opening project

Hi @JonesVid - When you have a project that you can reproduce this issue please send it my way and I'll be happy to take a look.  Thank You.

@jamieclarke I'm glad you are responding here. This feature is so useful, as we can use it for Smart Renders / quick Export, and cudos to @JonesVid for sticking with this thread.

Hi @jamieclarke 

Thanks for coming back on this. Much appreciated. The thread is a bit long.

My current project is probably not the best but I can try opening it next time and screen shot waht happens to some of the overlay transitions that are lost, even though they were successfully generated the first time.

I could also try just creating a small project to send to you to demonstrate what happens.

As mentioned somewhere in the thread, I have also had this happen when I have done some effects on a clip and rendered them (eg Noise reduction and Warp Stabilisation). Render it and all is fine, (Green line). Close project and re-open, then preview is lost (Red line) in Timeline.

Hi @JonesVid - I'm catching up with this thread,  Do you have a project that can always reproduce this issue in version 25.2?

It would be useful to get some sort of reply on this 'old problem' from Dev Team.

If you are not able to reproduce it - just get support to talk to me again - happy to oblige

No response from anyone at all is not very helpful

Hi @jamieclarke @Kevin-Monahan 

So the issue of Lost Preview files is still around - it ain't gone away !

I'm using Smart Rendering and my previews are all in Pro Res 422.

After a tip from Ann Bens I am only opening the sequence after all media loaded - this improves matters, but not all previews are there. See two examples below.

I'm working in H265 4-2-0 10 bit 4K UHD and previews generated are ProRes 422. this accelerates export massively on Export to a ProRes master to use for multiple types of Export as required.

The actual preview files are still there all intact in the Video Previews Folder. So they are not lost. Premiere cannot remember where there are.

As per my last note in December '24, the Support Team said this is being worked on but .... as of mid May 2025 no word on this yet.

The original post goes back to 2023.

My system has been updated since then to 128GB and a 4080 Super GPU.

The problem mainly shows up on short transition footage that is overlayed on a video cut.

When the project is opened and these are rendered all is fine.

Then, as usual on Premiere closure and re-opening the project soem are randomly are not available in the project timeline and you have to keep re-rendering them to generate a new Transition preview to relink it.

It can be reproduced quite easily.

Support have done at least 2 remote sessions with me on this during 2024.

I think its time this 'Lost Preview Pro Res ' bug was solved..

@jamieclarkeare you able to update us on this bug investigation  that Kevin Monahan confirms has also been filed internally ages ago?.

Support also have it on their radar.

Many thanks for any update on this.

cara tenho que falar, o PREMIERE é uns dos piores programas de edição que já trabalhei, o programa apresenta inumeros bugs, fica totalmente insustentavel trabalhar com ele, cada hora um bug diferente, cansei desse programa

Thanks for the update, well done! 🙂

Thought I would share my my latest update on the 'ProRes previews lost topic.'

After throwing my toys out of the pram on this one with support - a senior support guy phoned me last night to confirm what exactly was going on.

He confirmed 100% this is definitely being worked on by Dev/Engineering.

No timescales yet - but agreed it was taking a long time to see a fix. Indeed.

As expected,  a fix will appear in a Beta Release first - hope there is better visibility which one it is, rather than test each release.

Anyway, play the waiting game as no more we can do.

Nearly 2025 - problem still there.

Why Adobe , ????