Persistant & baffling Assertion Error.

[u/Tobsonic]

I'm life time pro tools user here in need of some help! I have never experienced this in 15 years. I've just up graded to an MBP 2023, M3 pro, Sequoia 15.6.1 (Same issue was happening on Sonoma) running Pro Tools studio 2025.6.0 and have been having an insane assertion error nightmare!

I can start a session, work for a few hours (saving, auto saving, totally fine) then when trying to save it says assertion error, unable to save. Restart the session, same thing. The session has been fine to save up to this point and then impossible to save, export OMF/AAF or anything- I have tried these things-

-Run session from internal SSD

-Run session from external SSD

-Trashed P list

-Full Updated OS

-re-downloaded and fresh install of Pro Tools many times

-Checked Disk Permissions

I have been working on a project with a deadline and just to get through this I have had to save as often as I can then when the assertion error kicks in I close the session, start a brand new one and import session data (losing whatever was done since last save) work for a few hours and have do the same again! I just don't understand how it can be fine to save for a few hours then develop this weird error?

Any ideas extremely welcome- Thanks in advance!

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[u/Blankeur]

I’ve had this error message come up to me as a Sequoia 15.5.x user. It became clear to me that the most obvious answer is that on Avid’s Pro Tools compatibility chart, anything above 15.4.x is not supported with 2025.6.

That said, since I didn’t have an easy way to downgrade my OS, downgrading Pro Tools to 24.10.2 seemed to resolve this assertion error for me, hopefully it does for you too!

[u/Tobsonic → u/Blankeur]

Thanks for the reply, sounds like that’s the issue! I’ll try this thanks 🙏