When an MP4 video doesn't play on Mac, you can search Mac App Store for a compatible MP4 player for Mac. You should search the right player with the name of the media format and filename extention (.mp4). To get the format, select the file and press Command + I to open an Info window. The format should be preceded by the label Kind.

As I've said before, for me. At one point, I realized that there were plenty of files on my Mac that I didn't need any more, but too many to delete individually. In other cases, your Mac can be experiencing some major malfunctions: constant crashing, locked controls, slow boot times, missing files, etc. Often, the best option to fix these problems would be to reformat your computer and reinstall your OS, but since most of us don't plan on ever taking this drastic measure, we don't obtain a recovery disc or thumb drive.

Thankfully, the geniuses over at Apple have made the process easy for us—no need for a disc; no need for a drive—all you need is a decent internet connection. With just a few clicks of some buttons and your Mac is gonna be running like it did the day you got it. Best of all, this will work with Lion,,,,. Step 1: Back Up Your Files! Okay, so you may have a lot of files that you want to get rid of, but you definitely have some files you want to keep. In my case, I even have programs I want to keep so I don't have to re-download them after the process is over. Use a writable CD/DVD, a, or any of the multitude of cloud options to keep your important files backed up.

You could also create a Time Machine backup, but I wouldn't do a full restore later—just pick and choose things you want back after a fresh install—otherwise it could run just as sluggishly or erratic as it did before. Step 2: Restart Your Computer Once you've double-, triple-, and quadruple-checked your backups, restart your computer. Step 3: Press CMD+R The second you see a grey screen, hold the CMD and R keys down for about 15 seconds, then let go and you'll be taken to OS X Utilities recovery. PLEASE HELP!!

Whenever I turn on my iMac, it would load up to the apple logo and shut down after a few seconds. Usb card reader for mac. This happened ever time i tried to turn it back on again. I had a bit of hope but nothing ever changed so I decided to erase my disk and was immediately promoted me to restart my computer. When I did, it brought me a a symbol of a folder with a question mark which flashed forever. I held the power button to turn it off and hit it to turn it on again while pressing command and R keys at the same time, it brings me a sign of a spinning globe that loads forever. When I restart it and immediately insert its installation DVD while pressing key C, it brings me the apple logo and stays like that for ages.