I just edited my post with some more detail that you may have missed.

I personally can't stand Windows, but in a few years I'll have no choice to use it or buy an Apple ARM -- Sonoma MIGHT be the last Mac OS I can run on it. My system is as fast as anything Apple makes, I have card slots, a fast GPU and it was built for half the cost of a Mac Studio Ultra. It will run linked, camera-original 4k, 6k and higher

I wouldn't buy an ARM Mac for Media Composer just yet... it's all over this forum how folks are having problems, and Avid is still not native. Conversely, the i9 would be great, but you have to understand you're buying a product that is now totally end of line for Apple, and may not be supported after a few years. J

The gotcha in doing this is the de-interlacing part, especially if some stuff has 3:2 pull-down. We used to use a Terranex to get us out of the changing cadences. If Topaz can't do it effectively (pretty sure it can), consider running it through one of those, if only to deinterlace prior to Topaz. Keep us posted, j

So, you have 'master' digital files from all sorts of formats (tape, and whatnot) that were SD, but instead of bringing those into Avid, you ran them through Media Encoder, changing them to 1920x1080, and instead of pillarboxing any of it, they're tiny little movies surrounded by black? Then, some were linked to Avid and some were imported

Wow, okay, you have me at a loss, sir.

If you're asking how to simply replace your SD clips in your timeline to your pillarboxed uprezes, there's no need to have to manually cut anything in. Determine which ones are needed, uprez (keeping the exact name and timecode as if were an identical file), bring those into Avid, and relink your sequence to those instead. You can even link

Hmm... might you have Legacy Codecs still installed? It's just very strange to me that you can Import QT movs at all -- from what I know, you shouldn't be able to since Catalina, but since I pretty much never transcode/direct import anymore, I absolutely could be wrong. It could possibly be that whatever quirk in your system is allowing you

You must be on an older Mac OS, then, if you can still import -- I can't import a QT on my end since Catalina (or was it Monterrey?). Can you submit your system specs? Even the Avid documentation recommends linking/transcoding as QT is not truly Apple supported (on later OS's), so if you still insist on straight importing (and you're not

What are your user/Link/Link Options set to? (Assuming you are "linking" to the file as opposed to "Importing") On my end, linking a ProRes4444 with alpha inverts every time (my settings have it set as such). j