Scrubby Zoom issues in Camera Raw

[jorchard13]

iMac 10.12.2, GTX 780M.  Running current CC 2017, Camera Raw 9.8.0.692.  All drivers and CUDA updated.  Use Graphics Processor is ticked.  When I open ONE CR2 file in Camera Raw, scrubby zoom works fine.  When I open TWO or MORE CR2 files, scrubby zoom is disabled.  What gives?  So frustrated.

[Trevor.Dennis · Accepted solution]

Same thing here with Windows 10.  It's as if it is trying, but not quite making it. Fine with one file open.  It breaks with two or more.

I left it for a while in case was busy building previews or some such house work, but it made no difference.  I actually had to re-enable GPU in ACR Preferences to test this, as it tends to cause other problems for me, but I'll leave it turned on for now.  Unfortunately I don't take a lot of pictures nowadays (I work from scratch) so issues might be a while in showing up.