Chances are it'll only be the Timeline setting that needs fixing. So with the Settings pane open go File>Open Settings File and drag a default Timeline setting into your settings (you may need to create a new vanilla user setting first if you've customised the only user setting on your system), choosing 'replace' and then you can

Oh yes absolutely. I was thinking you wanted something that could be expanded and re-edited. If you make video and audio mixdowns of the desired portion you can then sync them together to make a single clip that is independent of the original media.

'Collapse' or 'Submaster' kind of do this but not quite ie they work within the timeline to simplify the view and to enable you to add an effect to a section of already layered shots but I don't thinnk you can save them to a bin and re-edit them into another sequence. You can copy and paste them from one seq to another though.

Have you tried deleting the pmr and mdb files and letting 8.4.4 rebuild them? There's no reason for the media to be incompatible as MXF DV420 is still supported. The database files might not be compatible though, or could have become corrupted.

I don't know about the old mojos but the dx versions work. FWIW I recently did this into 8.9.2 over firewire from a DV deck and also over USB3 with a BM Intensity Shuttle using S-Video from deck/cam. I did have some issues with the Firewire method but the tapes were long play dv with 8 bit/32k audio, the 'proper' DV tapes all worked fine

And the OS error; Not sure if this is something that can be fixed by OS/client upgrade or prefs trashing etc or something that our Information Services dept (who are responsible for the network) need to fix. Are there any network settings etc that could cause this? Specifically ones that may have different reqs for mac and PC?

We have a Nexis system with a mix of PC and mac clients and the macs all exhibit this error when trying to copy files to a workspace. Sometimes the files will copy anyway but others will throw up a further OS error. Sometimes Errcode 0x9, sometimes 0xd

I'm having this bug show up in 25p projects (all 25p media and project not fim enabled) when I have more than 4 video tracks. Is there any way to solve it?

I've never had good results getting h264 out of avid (at leats with any sequence over ~5mins). I'd always do a QTref or SaS and then convert in MPEGStreamclip/Compressor/Reolve etc.

I lean towards the Blackmagic boxes at the mo because I find Resolve to be an invaluable addition to the suite so the ability to have broadcast monitoring from it is a big plus.