Resolve's cache defaults to your system drive and grows per project

Resolve generates a great deal to make editing smooth, and on Windows the default cache location is your fastest drive, which is usually the system drive. None of it is removed when a project finishes.

Finding the cache

Get-ChildItem "$env:USERPROFILE\Videos","$env:APPDATA\Blackmagic Design","$env:PROGRAMDATA\Blackmagic Design" -EA SilentlyContinue |
  ForEach-Object {
    $s = (Get-ChildItem $_.FullName -Recurse -Force -File -EA SilentlyContinue | Measure-Object Length -Sum).Sum
    [PSCustomObject]@{ MB = [math]::Round($s/1MB); Path = $_.FullName }
  } | Sort-Object MB -Descending

The location is set in Preferences, Media Storage, and per project under Master Settings. Checking where it actually points is the first thing to do, because the default is rarely where anyone would choose.

What is in it

Clearing it properly

Inside Resolve: Playback, Delete Render Cache, with options for unused or all. Optimised media is removed per clip or per project from the media pool's right click menu. Both are better than deleting folders, because the project database tracks what exists.

Moving it off the system drive

If you edit regularly, pointing the cache at a second drive is the single change that keeps C usable. It is a preference rather than a cleanup, and it means the folder can grow without ever being your problem. Windows makes this easier than most: a second internal drive is common, and Resolve is happy with it.

The project database

Resolve keeps its projects in a database rather than as files, and its backups live alongside. Those are small and are the one thing here you would genuinely miss, so leave them alone. The same distinction between derived data and work applies to every editor.