I am part way through a project that is likely to take me a while to complete, I just noticed that I never did apply the 9.0c upgrade (I was certain I had - must be old age creeping up!).

Anyway, I was wondering if it was 'safe' to up-grade from 9.0b to 9.0c when you are half way through a project as 9.0c may have some advantages

You're free to do as you please but my upgrade rule of thumb is "Never in the middle of a project, no matter how small".
Are you having specific issues that 9.0c would hopefully solve?

Hi Mike, not that I am aware of... the only problem I have had in the past is Vegas causing the PC to freeze up then shut down on rendering, but I 'think' I've cured that.

Philip, if you really want to do this, please don't let me stop you.
Some suggestions for you though if you don't mind.
If you don't already have a back-up copy of 9.0b on your hard drive, get it on the Sony site (http://download.sonymediasoftware.com/current/).
Before you do the upgrade, save the current project out as something like "Philip-90b.veg" so that you know it was done with that version.
Save it again but as "Philip-90c.veg" this time and use that version when you open up 9.0c for the first time.

Thanks for the tip Mike