This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
A: The version of fdisk that comes with many Linux systems creates partitions that fail its own validity checking. Unfortunately, if you've already installed your system, there's not much you can do about this, apart from copying the data off the partition, deleting and remaking it, and copying the data back.
You can avoid the problem by getting the latest version of fdisk, from Rik Faith's util-linux package (available on all the usual FTP sites). Alternatively, if you are creating a new partition 1 that starts in the first cylinder, you can do the following to get a partition that fdisk likes.
*Create partition 1 in the normal way. A p listing will produce the mismatch complaint. *Type u to set sector mode and do p again. Copy down the number from the End column. *Delete partition 1. *While still in sector mode, re-create partition 1. Set the first sector to match the number of sectors per track. This is the sector number in the first line of the p output. Set the last sector to the value you wrote down in the step above. *Type u to reset cylinder mode and continue with other partitions. Ignore the message about unallocated sectors. They refer to the sectors on the first track apart from the Master Boot Record, and they are not used if you start the first partition in track 2.