topic EOS R5 One 4K video won't transfer via USB, others will in EOS DSLR & Mirrorless Cameras

EOS R5 One 4K video won't transfer via USB, others will

kuba_ma — Thu, 20 Nov 2025 13:21:37 GMT

Hi. Regarding this topic... I recorded several videos in one session. All with the same parameters (4K). The longest one was about 8 minutes. I can transfer all the videos using a USB-C cable except this one. Only the camera sees this video, and I can only send it from the camera to my phone via Wi-Fi. It takes up over 5GB. When I see it on the card, it takes up 0b. What's going on?

Re: EOS R5 One 4K video won't transfer via USB, others will

johnrmoyer — Thu, 20 Nov 2025 13:58:41 GMT

One might guess that the maximum for at least one piece of software involved is 2^32 = 4294967296 bytes. This was common in ancient times.

Re: EOS R5 One 4K video won't transfer via USB, others will

shadowsports — Thu, 20 Nov 2025 14:27:01 GMT

Greetings ,

Is the one file that won't transfer RAW (8k) or XF-AVC (4k)?

If so, these file types require a card reader for transfer.

MP4 files are not subject to this limitation.

Re: EOS R5 One 4K video won't transfer via USB, others will

kuba_ma — Fri, 28 Nov 2025 08:35:44 GMT

Thanks.
I have 4K-U 25.00P XF-AVC 420 8bit
This is crazy, becouse smaler files - no problem, only longer...

Re: EOS R5 One 4K video won't transfer via USB, others will

johnrmoyer — Fri, 28 Nov 2025 11:42:44 GMT

If smaller files work, but not larger files, then if the larger file is more than 4GB and the smaller files are less than 4GB, I expect it is a software problem. At times in the past, the limit has also been 2GB.

What is the maximum file size that works? At what file size does it stop working?

For a 32 bit unsigned integer, the range of values that can be represented is zero to 4294967295 and for a 32 bit signed integer, it is half that.

Much software still uses 32 bit integers. Some software uses 64 bit integers.

If the software that is the problem is built into the camera, then you will be limited to 4GB files for USB transfer and need to use a card reader for larger ones. If the software is in a computer, then using different software or upgrading the computer would be the solution.

Re: EOS R5 One 4K video won't transfer via USB, others will

kuba_ma — Fri, 28 Nov 2025 11:46:30 GMT

This is very possible. But problem is only with download using USB. WiFi is correct

Re: EOS R5 One 4K video won't transfer via USB, others will

johnrmoyer — Fri, 28 Nov 2025 12:23:12 GMT

wifi uses different software than usb

Re: EOS R5 One 4K video won't transfer via USB, others will

stevet1 — Fri, 28 Nov 2025 14:07:24 GMT

kuba_ma,

Another alternative would be to break up your longer videos up into smaller segments.

Instead of one 8 minute video, break it up into 2, four minute videos.

Steve Thomas