You could try using the Playlength command to improve responsiveness. If you're not sure what this is, it's been discussed before in the forum. See... https://community.avid.com/forums/p/88639/503153.aspx

I would also check that when you've got your bin full of DNX36 clips, that you see they have Source File Name metadata. You can do this by adding this column to the bin view. Having this metadata is needed to relink back to the original rushes in Resolve (or whatever). If this data isn't there, check the Tape column and see if roll numbers have

Been a long time since I opened up one of these machines! Are you talking about these instructions?... https://www.manualslib.com/manual/831742/Sony-Dvw-A500p.html?page=23#manual You should be able to remove the top panel first, which should allow you to remove the side panel (Sony refer to it as 'Plate MD')

I appreciate that Avid have never been quick-off-the-mark compared with some other companies, but these problems with issues due to upgrades have been around for years with all sorts of software. - and I'm talking both Mac and PC operating systems. A lot of post facilities are still running systems with Windows 7/Catalina and MC 2018, simply because

Could Tentacle be doing something to the files that Avid doesn't like? Strange that it would only be doing it to some clips and not others. Not sure why you're using this software as Avid will happily sync up video and audio using autosync. Since you say the original clips will link fine, could you try doing this to one of the problem clips

This is a common problem when sending video to an external display - is this what you're doing? It happens because most LCD/LED displays have a delay in actually displaying the video on the screen, compared to the audio. People who have home cinema systems see this when they route their audio (from say, a Blu Ray player) to their home hifi systems

I was thinking that it could be something to do with the old quicktime 32bit codecs, which I believe are not included in Big Sur (which is all 64 bit) but that doesn't explain why half of the clips will relink and others won't! Is there any common factor in the clips that won't relink? Could they be spanned clips?

I've a dim memory of having seen this in the past and it was related to Time Machine. Switch TM off and see what happens.

Before you look for a way to do this, have you asked her why she's changed her mind? The mixdown tracks are usually for monitoring purposes and wouldn't be used in the final dubbing session. Is the edit going for a sound dub in something like Protools? If so, you'd usually want to include the separate audio tracks that were recorded. Assuming

Not working here. clicking on 'download' just blanks the screen for a second, but nothing downloads. Tried on various browsers.