How to fix your Mac's Bluetooth connection...

 Mac's Bluetooth connection keeps dropping and my mouse skips or just stops working. What can I do to fix this?

 Power-management issues and signal interference from other devices are often the root of Bluetooth connection problems, but start your troubleshooting steps by making sure your system is up-to-date and you have the latest drivers installed. Turning the Bluetooth connection off and on may help. You can also try deleting the mouse's profile from the Bluetooth settings and pairing it again with the computer.
A weak battery in the mouse can lead to a dropped connection, so recharge or replace the mouse's batteries to see if that helps maintain its link to the computer. In OS X, you can see the battery's strength when you click the Bluetooth icon in the Mac's menu bar; select the name of the mouse from the Devices list to see the battery's percentage level.
If you hold down the Option key while clicking the Bluetooth icon in the Mac's menu bar, you get access to several diagnostic tools for tracking the quality of your Bluetooth connection; these may not mean much to nontechnical users, but they can be interesting to explore. You can also see the Received Signal Strength Indicator number, which can give a general idea of your connection strength. (Basically, 0 to -60 decibel-milliwatts is considered strong, and the connection gets weaker as the RSSI value goes from -61 dBm to -90 dBm.)

Wireless devices can suffer from interference generated by other wireless systems, especially those that operate on the same 2.4-gigahertz frequency that Bluetooth uses. Cordless telephones, baby monitors, wireless speakers, cameras, wireless network routers and other devices nearby can cause interference and dropped Bluetooth connections, as can microwave ovens.
Other types of interference that are emitted from external monitors, or the cable and connectors used with satellite dishes, have been known to cause Bluetooth issues -- as can electrical interference from sources like circuit-breaker boxes or power lines. Changing the location of the computer may help. Materials like metal, plaster and glass can also interfere with wireless connectivity, so if you are using the mouse on a keyboard tray that pulls out from under a desk, try moving your equipment so that the metal and other materials are not between the mouse and computer.