Red RD3 files black on import with audio

Do you have the appropriate plugin?

Import REDCODE RAW files into Final Cut Pro – Apple Support (UK)

Here are a few more things:

create a new library, import some RED clips; any difference?

delete and reinstall FCP; any difference?

if the problem remains: Please run Etrecheck and post its full report here.

Use the “additional text” button and paste the report into the text box.

There could be other issues and the report could help us find them.

By the way: do you have Chrome?

Switch off MalwareBytes if it's running. Where's the media stored? It sounds like the drive is slow if the filmstrip is only loading intermittently.

try deleting preferences

you may also want to update the OS to 12.3.1 (Beware: it appears that tape cameras are not working since 12.3; if you don’t have any, go ahead as there were several bugs fixed since 12.0.1)

Does FCP have Full Disk Access in System Preferences->Security & Privacy->Privacy? It needs it.

Chrome and its evil keystone daemons are poisonous to video applications like FCP.

See https://chromeisbad.com for an explanation.

I recommend that you uninstall Chrome and the keystone daemons (see the site above for how), then delete and reinstall FCP.

If you need stuff that is made for Chrome, try other Chrome based browsers like Brave, Edge or Opera. These do not use the keystone things that cause so much trouble.

I've never used RED media on a spinning drive so I can't say how well it would work.

If you don't have MalwareBytes on the system it would be an idea to do a Finder system search to remove the remnants that seem to be there. They might be running in the background.

It may be a camera specific problem. The RED media I have all works.