Error message: "Insufficient Space " for photo import – APFS filesystem macOS

Hi all,

I get the beloved "Not enough disk space on drive "whatever". Please free up another xx GB to proceed" message.

• I want to import about 150 GB of photos. 
• LR told me to free up 44 GB. 
• "About My Mac" - "Storage" tells me there's 311 GB available.
• "Disk Utility" tells me there's 106 GB of free space.

So, from reading and hearing stuff about APFS, I know that the difference between those 311 and 106 GB is probably what APFS calls "purgeable space". Therefore I'm betting the communication between Lightroom and macOS doesn't work and Lightroom thinks only the 106GB are available. 

Since APFS lets the drive fill up quite a bit, this is a problem for me constantly, even though I'm on a 1TB drive which isn't more than 50-60% full and my LR catalogue is only 200GB total.

Currently I'm working around this with a terrible Terminal hack that just made my MacBook crash, so it's not a great situation.

I know this is one of the instances where the cloud model just isn't ready yet (because LR needs to copy the files before importing, hence the huge overhead needed in the first place), but as I said, it's probably also "just a bug".