My MacBook screen has been switching randomly

My MacBook Air keeps switching between desktop and full screen apps by itself

There are several possible causes for this issue. Take each of the following steps that you haven't already tried until it's resolved. Some may not be applicable.

1. Follow the instructions in this support article, and also this one, if applicable. A damaged or defective AC adapter could be the cause, even if it's the right kind.

2. Open the Bluetooth preference pane in System Preferences and delete all pointing devices other than the trackpad, if applicable. Disconnect any USB pointing devices. By a "pointing device," I mean a peripheral that moves the cursor in response to user input, such as a trackpad, mouse, trackball, or graphics tablet. A plain keyboard is not a pointing device.

3. Boot in safe mode and test, preferably without launching any third-party applications. If you don't have the problem in safe mode, but it comes back when you reboot as usual, stop here and post your results. If you can't boot in safe mode, do the same. If you booted in safe mode and there was no change, go on to the next step.

4. Reset the System Management Controller.

5. If you're using a Bluetooth trackpad, investigate potential sources of interference, including USB 3 devices.

6. A swollen battery in a portable computer can impinge on the trackpad from below and cause erratic behavior. If you have trouble clicking the trackpad, this is likely the reason. The battery must be replaced without delay.

7. Press down all four corners of the trackpad at once and release. If there's any effect, it's likely to be temporary, and the unit needs to be serviced or replaced.

8. There's a report that a (possibly defective) Thunderbolt Ethernet adapter can cause the built-in trackpad of a MacBook to behave erratically. If you're using such an adapter, disconnect it and test.

9. There's also a report of erratic cursor movements caused by an external display that was connected but not turned on.

10. If none of the above applies, or if you have another reason to think that your computer is being remotely controlled, remove it from the network by turning off Wi-Fi (or your Wi-Fi access point), disconnecting from a Bluetooth network link, and unplugging the Ethernet cable or USB modem, whichever is applicable. If the cursor movements stop at once, you should suspect an intrusion.

11. Make a "Genius" appointment at an Apple Store to have the machine and/or external trackpad tested.

I have the same problem and it drove me nut with mouse jump around and sometimes swithching apps as if someone is controlling the computer.

What I found was that my battery is too old and is bulging. With bulging battery, it presses the back of the touchpad, and makes it fires false signals.

To solve this problem, here are some of the options I did:

1. Take the battery out, and check for bulging spot. If it is present, use a needle to carefully punch a hole in the membrane to release the gas, and then tape the hole. This is temporary measure and you should replace the battery with a new one.
2. Replace the battery with a new one if it is too old.
3. Disable the touch pad. Go to System Preferences --> Accessibility --> Mouse & Trackpad --> Check the box "Ignore build-in trackpad when mouse or wireless trackpad is present". Use your external mouse or wireless mouse instead.

I found option 3 immediately fix the problem, but you need to take other measures to fix the cause.

All windows on my MacBook Air were reducing and enlarging in an out from mission control. I tried unchecking all the settings in Mission Control but nothing worked. I disabled Bluetooth and the switching stopped. I kept getting a message that the batteries in the Apple mouse were low so I am surmising that since the switching stopped after disabling bluetooth, low mouse battery warnings must be the reason. This has never happed before when the mouse batteries were low so maybe a bug. I am running Yosemite 10.10.4.