micro sd card will not format

I use a Pentax K20D , I recently purchased a 64gb micro sd card (i do not recall the brand name, reltively unknown).as a new card I formatted on the camera. When I attempted to use the camera the day after the "card not formatted " message appeared .Any attempt to format the card failed.Any suggestions as to cause......Nadeem

Not sure the K-20 will take a card that large. If it does then ensure you have the latest firmware.

Same thought. K20 will only take SD and SDHC cards NOT SDXC. That limits capacity to 32GB.

As an experiment, set up the directory structure with et card connected to a PC and then try - but I think it will fail as SDXCs use exFAT file system and the K20 is FAT32 compatible.

I have a K20D. Will only take SDHC cards, max 32gb.

Nadeem - Like the other guys have already said, 64Gb may be a bit of a behemoth for your camera to handle... Typically, a jpeg will measure on average 4-5 Mb - approx 200 images per Gb.. Do you seriously intend to take and store 12,800 jpegs on one card?? Most of us here will (at a push) go no higher than a 16Gb card, and from a "reputable" (Sandisk, Kingston, etc) card manufacturer, although I've recently been using Pretec cards. I'd recommend you use the 64Gb card for use in something like a tablet or smartphone, and only for storing large chunks of data (movies, for example) on it, using the card only on occasions. Get yourself a couple of 8GB 0r 16Gb cards. Honestly, it's worth it! Imagine losing all 12,800 jpegs from that card because it became so badly corrupted that the files become irrecoverable? Also consider making back-ups of your shots onto recordable media - once again, using well-known brands, and avoid the discs that they sell in the pound shops!

If it helps I only use 2, 4, or 8GB cards on the basis that the failure of one card does not mean the loss of all my pictures. These are either Sandisk or Hama.

I've never felt I had a limitation on the number of pics I could take (even on holiday)

regards
Bernard