The disc partition mistake. The disk is defined as dynamic. The data are necessary.
During the information recovery Seagate 200 Gb, disc filled with valuable information specially prepared for a trip to Stavropol, at power on informed that its partition was not NTFS, but a dynamic one.
Such a problem happens very often. It is caused, as a rule, by hardware problem at the controller/connector level, or by operational system failures. If only one incorrect byte is registered in the partitions table, or in the boot sector, the OS refuses to sense the disc logic content. The situation is not too serious. However, I do not know a program which could cope all over with it in the automatic mode. The best way is to load well known and reliable DiskEditor (or some other software, capable to work with a disk at the LBA level in Hex mode) and correct mistakes in the necessary parts manually. Knowledge of logic marking features and a file system can be of great help.
Hex editor
The service on recovery of initial structure of a disk logic marking is inexpensive if the situation has not been complicated with the user incorrect actions, as a number of automatic recovery programs can do much harm instead of help in such a situation.