Date: 2021 June 30 — I have two X-T4s — one about 14 months old, the second about 5 months old (with 70-300 — fantastic lens). Yesterday I updated the firmware to 1.21. Last evening, I took one of my X-T4s to a baseball game and for the VERY FIRST TIME EVER I experienced frequent lockdowns or freezes. After taking a photo, the LCD would go black, the orange data transfer light would come on and stay on. Switching the camera on and off made no difference. The only solution was to remove and reinstall the battery. The camera would then work properly for a few more frames and then repeat the lockdown process again. That probably happened 6 or 8 times last night in an hour. This morning I repeated that scenario about 5 times. It has been suggested that the problem is related to SD cards; I had the same problem with different Lexar cards that have never failed. So it doesn't seem to be related to SD cards. Unfortunately, the defect appears intermittent; i.e., I cannot recreate the failure upon command. I have noted on Fuji-Form that a lot of people have reported similar behavior for X-T4s, but not X-T3s. Have you seen this problem in your X-T4? Do you know if the problem is unique to specific cameras or to specific versions of firmware? Do you know if Fuji is aware of the issue? Do you know if they are working on the problem? In a word, this is now a major pain in the butt.
Davidson, North Carolina