Can't use 4GB SD card

What model Praktica camera? Is it compatible with SDHC cards or only with SD cards?

Make sure you have an SD card. If your card is 4GB or larger then it's actually an SDHC card and won't work in your camera.

Unless you've found a VERY rare 4GB SD card, your 4GB card is actually an SDHC card. The 610 will not work with SDHC cards. Try using an SD card, 2GB and smaller.

The M415 works with SD cards. Your 4GB card is actually an SDHC card and won't work with the camera. You need to use SD cards, 2GB and smaller.

The Optio S4 works with MMC and SD cards. Your 4GB card is actually an SDHC card. While it fits into the slot, it is electronically incompatible. You need to go with cards 2GB and smaller.

The S50 uses SD cards. Your 4GB card is actually an SDHC card, and will not work in the S50. You will have to confine your choices to cards 2GB and smaller.

1. Try to format your memory card using a PC/Laptop.

2. Now, insert it in camera and check whether its working!

please rate this advice if it helps....tc! :)

The S4 accepts SD and MMC cards. SD cards max out at 2Gb. The 4Gb and 8Gb cards are actually SDHC (Secure Digital High Capacity) cards, not SD cards, and thus will not work in devices designed for SD cards. Compatibility goes only one way--SD cards will work in SDHC devices but not the other way around.

Is the slide switch in the unlocked position? Are you formatting it in the camera? Are the card contacts dirty?

Memory card support : SD/MMC up to 2 Gigabyte and SDHC up to 8 Gigabyte

Pls. use the supported SD card.