But there are also instances where the slide switch will not correct the problem. One example is trying to use a 4GB or higher SDHC card with an older camera made before SDHC format came out. There are also other common causes if the above didn't help, with troubleshooting steps for this problem [http://camerarepair.blogspot.com/2009/07/simple-fix-for-memory-card-locked-error.html|listed here].