Wed Jan 20, 2021 8:53 am
Generally, a media offline error means that your original files have moved or become unavailable since you imported them. It can happen for any number of reasons. If you change the name of a folder anywhere in the hierarchy of folders which contain your media, for example, the media will go offline. Or, if your media lives on an external drive, and you eject the drive, the media will go offline. Or if you're accessing the media over a network, and the network becomes unavailable... you get the idea.
So changing folder names and moving stuff around in your system is generally how you get yourself into trouble. The way you fix it is by reconnecting your media in Resolve. If you're on 17b, there's a red, broken chainlink icon that you click to initiate the process. In versions prior to 17b, you can right-click on the item in the media pool and choosing either "relink selected clips..." or "change source folder..." The difference between the two commands is described on page 322 of the Aug 2020 user manual, but basically the re-link command will do a recursive search for target files, and "change source folder" won't.
The folders you're talking about deleting are for your render cache. Your cache is internally generated and managed by Resolve. You shouldn't mess around with it outside of Resolve, but if you do, Resolve will invalidate the previous cache and generate a new one. I think there were issues with previous versions of Resolve caching out the red "missing media" graphic, but I'm not entirely sure that's what was going on. Networked setups also used to behave differently with respect to render caches. Like Peter said, we'll need to know more details about your setup to be able to help, but we'd be glad to help.
Oh, and there's also a difference between unlinked and missing clips, and they both have different badges. See page 898 of the user manual for that info.
And lastly, I know it can be frustrating and stressful when you see red badges, yellow exclamation points, or whatever. They are a part of every NLE, and every editor panics a little on the inside whenever they pop up. You get used to it. I've worked in FCP7, FCPX, Premiere, and Resolve. It's not a Resolve-specific problem, but a consequence of your NLE being a separate system from your OS; it's just a fact of life.
-MacBook Pro (14,3) i7 2.9 GHz 16 GB, Intel 630, AMD 560 x1
-[DR 17.0 Beta9]