How to stop Time Machine on Mac use of removable disk?

Question

One of my friend recently bought a Mac and somehow when she connect her removable disk to the computer, Time Machine took control of this device uses it as backup device automatically -- she could not use the disk for other purpose any more. When we connect it to windows, it could not be recognize any more.

How can we get it back under control?

Answer 1

Windows does not see it because the disk is formatted in Mac filesystem.

To be able to use it, disable Time Machine (in System Preferences, or from the Time Machine menu), then reformat it using Disk Utility (in the Utilities folder of Applications).

It is a good idea to reformat it with two partitions: one for Time Machine, and another for his datas. Maybe he'll want to format the data partition in FAT32, so that he can read it also from a PC.