Sandisk 64gb ultra

camera doesn't support 64gb, try 32gb or lesser

It may be a correct physical size (SD card) but other factors also matter
- un-supportted file system (SDXC is exFAT)
- max addressable space (gb) by the device
- support speed (Class #)
see Speed Class SD Association
- higher processors for Ultra Hi Def recording at higher frames will need higher speed

My suggestion is
(a) verify if your camera has a newer firmware that could support high capacity. if not...
(b) do not format on the camera because it may limit it in size.
(c) use this 64gb on other device like laptop.
(d) sell it on ebay
Prefer newer memory format like MicroSD with microSD adaptor/ holders

Did you buy it off of eBay? There are a lot of fake name brand SD cards sold there. If you got too good of a price, it could be a fake. There are free programs available to analyze your card. Look for a program called how to check capacity of your card . If you did buy from eBay, file for a refund.

The XP10 works with SD cards, 2GB or smaller, and SDHC cards, 4GB to 32GB. It will not work with 64GB SDXC cards.

Put your drive into a USB port; right click on that drive after it appears in My Computer and select Format; set the File System drop-down to NTFS (better file storage space) or FAT32 (more compatibility in older operating systems) and click Start.

I ran into this exact issue (64GB Sandisk SD not working with an old Nikon D40). The problem is that the camera requires FAT32 formatting, which is not supported on partitions greater than 32GB (i.e the 64GB stick). A format from the camera attempts to repartition all device space (64GB) which is incompatible.

I solved this by connecting the SD to my laptop, opening the windows disk management utility (diskmgmt.MSC), deleting all partitions on the SD (right-click, delete partition on all allocated space), the right clicking the unallocated space, add simple partition, then allocating only 32GB and using FAT32 as the format (any more and windows will only provide exFAT as an option, also not compatible with Nikon D40). Plugging that into the camera and NOT reformatting from there worked.

No, you didn't loose memory. You just have to reformat it. When you do, check if you can change the total capacity with drop down menu, also try settings it to FAT32.

If not, you could use another computer or even a portable device like cellphone or camera to try and format it.

Don't worry, you cannot 'loose' the 64gb.

The camera uses FAT16 so it won't be able to use cards bigger than 2GB. IF you can format it, you will only have 2GB space available.
Formatting the card: Press Menu/OK, select Setup, Select Format, press OK untill it's done.

You may need to format the card. There should be a Format command in the Setup menu. To be more specific, one would need to know which model of Finepix camera you refer to.