How to change LR's scratch disk?

[JacquesCornell]

When I try to Merge to Pano, LR is filling my boot drive (which started with 50GB free) and paralyzing my Mac. How can I designate an external drive for scratch? I've designated an external drive for Camera RAW cache, to no avail. I mean really, this is just totally unacceptable.

[Mohit Goyal]

Hi JacquesCornell,

Just wanted to check, is this starting happening after Lightroom 6.10/2015.10 update?

Thanks,

Mohit

[JacquesCornell]

I've done small panos before, up to 12 frames or so. But, I first tried a 39-frame merge today after updating to the latest version.