My working RTK Surveyor was shipped with v2_6 firmware. By turning on PPP messaging options, I was able to generate ubx files that were supported by Emlid Studio. This was true even when the device was turned off to stop the logging, in other words I’d always get a file on the microSD like “SFE_Surveyor_dateness_timeness.ubx”.
After updating to firmware v3_2, often when I turn off the device, I instead find a file on the microSD named “SFE”. It has the right size, the right content, and if it’s renamed something like “SFE_Surveyor_dateness_timeness.ubx”, it works just fine with Emlid Studio.
I also switched card brands (Samsung vs SanDisk), and have ridiculously few datapoints, so this may have been a legacy bug.
Minor PITA with a not-too-hard workaround.