FCP: library size discrepancy (also, how to clear "cache"?)

Question

FCP: library size discrepancy (also, how to clear "cache"?)

Hi folks!

Now that I'm done a project, I thought I'd free up space on my hard drive. By doing all the "Delete Generated Library Files...", I got my 250GB library down to about 44GB.

But it still seemed high, especially when I looked at the library properties in the inspector a few days later. So I repeated the procedure, and the numbers in the inspector dropped a good bit more.

At this point I have two questions:

1) I see that I have 8.7GB in "Cache". Cache is not under the list of generated files or otherwise something that I have found a delete option for. Can the cache be deleted? Is it a supported function to do so? Is there a down side to doing so?

2) Per the Finder, my library is still 44 GB on disk after the latter operation. But I can't tie that out with the numbers I see in the inspector, which appears to claim that it's really just 17.9 GB. Whence the discrepancy, and how can I recover the ghost space?

Thanks in advance!

Posted on Oct 25, 2024 6:55 PM

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Answer 1

Tom Wolsky

Level 10

151,971 points

Oct 25, 2024 7:07 PM in response to Dave Kitabjian

Yes. Move the Cache out of the library. In library properties set the Cache outside the library to the same folder or location as the library. It will appear as a bundle next to the library with the same name. Simply dump the cache whenever you want. Whatever the application needs for the library it will rebuild into a new cache bundle when the library is opened.

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Answer 2

Oct 26, 2024 8:36 AM in response to Dave Kitabjian

It's annoying, but I think the Finder or the underlying file system need time to recover disk space, or at least to update their accounting. So perhaps I just needed to be more patient.

Such changes are only reflected when either the library is closed, or you quit FCP.

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Answer 3

Oct 26, 2024 8:10 AM in response to Tom Wolsky

Thanks, Tom!

Before I do that or touch anything, I want to point out that having let the Mac sit overnight and checking this morning, the file size of this library, from the point of view of the Finder, has now apparently caught up and matches what FCP says in the inspector:

It's annoying, but I think the Finder or the underlying file system need time to recover disk space, or at least to update their accounting. So perhaps I just needed to be more patient.

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Answer 4

Oct 26, 2024 8:29 AM in response to Tom Wolsky

Okay, next update:

I now took your suggestions and moved the Cache outside the library. As per p. 830 in the manual, it does ask me:

"If you changed the cache storage location, you’re asked if you want to move your existing active render files to the new location."

and I said to do so. At that point, it promptly created a nearly 9 GB bundle in the folder I created beside my library, and the library itself shrunk by the same amount. Perfect.

I then deleted the cache, and then tried playing back my project in FCP, and it began rebuilding the render files, as promised. Feeling safe, I went back and deleted the cache files again, to free up disk space, and now have a fairly compact library to archive.

THANK YOU!

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Answer 5

Oct 26, 2024 9:48 AM in response to Luis Sequeira1

> Such changes are only reflected when either the library is closed, or you quit FCP.

Yes, thanks, Luis. It did occur to me that the application may have held the files open, and that they may have been locked from a filesystem point of view, and therefore not "free up" until FCP was quit. That's why I'm pretty sure I fully quit FCP and let it sit that way for a while, and still not free up the local space, before I raised the question.

But I'll note that, first of all, my Mac reported that it had rebooted overnight due to some problem. Was that the issue? Also, I do have both Time Machine and Arq running backups on my Mac, and I'm not sure if their operations on this newly modified library could have locked files for a period of time, too.

Next time, I might watch to see if backups are running. But I'll also be a bit more patient, and trust FCP's inspectors

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