My quicktime player on os x 10.9.5 stopped working

My default Quicktime Player that comes with OS X 10.9.5 stopped working. When trying to open, I get a "Problem Report QuickTime Player" with options "OK" and "Reopen". Neither option works. Needless to say I can not play any videos. This is NOT due to upgrades, it was working but overtime it started developing problems. I think it just got damaged or corrupt and needs to be reinstalled. This is on a Macbook Pro with OS X 10.9.5. This Quicktime ver (10.3 I think) came with the OS.

Tried to uninstall it but get a message that Quicktime is part of the OS, so I stopped. Also don't know where I can get a copy of this ver of Quicktime Player.

So I'm not sure what the process is to fix it. Any pointers for this new Apple newbe would be appreciated.

Is the problem local (shows up in only user account) or global (shows up under all user accounts)? If local, then the problem may only be a corrupted PLIST file for QT X in that account's "Preferences" folder. If global, then the problem may be corruption in the app itself, the operating system or some sort of software conflict. In most cases a global problem is more easily fixed by re-installing the entire system than by trying to diagnose, isolate, and fix a specific problem. Another possible solution (if you have a spare external drive), would be to create a pristine, secondary start-up system and use it to troubleshoot the original system problem which can be a lengthy, time-consuming proposition.

So I went into the library and deleted the following, ONE at a time:

com.apple.QuickTimePlayerX.LSSharedFileList.plist

com.apple.quicktimeplayer.plist

com.apple.quicktime.plugin.preferences.plist

and

QuickTime Preferences file

As stated, I deleted each file individual, one at a time and rebooted the computer after each delete. I was expecting the OS to rebuild these files by itself but I could NOT find these said files anywhere again. Maybe I did something wrong? I put back the files from the trash bin to original location for now.

1) I believe the file you want to delete is "com.apple.QuickTimePlayerX.plist" located in the "Library > Preferences" folder for the account under which the QT X player crashes. (I.e., each user account should have its own PLIST file for the QT X player app so make sure you didn't delete the one for the working user account.)

2) You normally don't have to re-boot the system after deleting the PLIST file—but you do have to close and/or re-open the player app under the user account having problems to force the creation of a new PLIST file. Alternately, you could try replacing the bad PLIST file with a copy of the working PLIST file.

Also, you wrote "com.apple.QuickTimePlayerX.plist", but the closest file I can find to that is com.apple.QuickTimePlayerX.LSSharedFileList.plist.

You may be correct here. I erased a spare external drive and installed a clean version of the latest Mac OS X system and "com.apple.QuickTimePlayerX.LSSharedFileList.plist" was the only QTX name that popped up. (I.e., it appears the name I suggested was a carryover from an earlier OS version.) Also learned the following....

1) To force the system to generate a new copy of the "com.apple.QuickTimePlayerX.LSSharedFileList.plist" file I had to open the QT X player app and load a media file for playback. (I.e., merely rebooting the system does not regenerate this PLIST file nor does merely opening the app as it used to do under older operating systems.) On my system I either "drop load" a file to the QT X Player icon or open the app and select a file for playback.

2) When forcing the regeneration of this PLIST file, invalid file/path references are filtered from the "Recents" list automatically.

3) Structure of "Shared" PLIST file is different from the QT X Player PLIST file I references. Believe this change was the result of combining the old player PLIST file and individual PLIST files that used to be created for each individual media file played. (I.e., the "Shared" PLIST file stores bookmarks, custom property info, and names of the most recent filles played. For example:

4) Am guessing, but cannot confirm, that if this file becomes corrupted or the references become orphaned, then that might explain why the QT X player might crash. (I.e., am hoping that the process of regenerating this file might might filter out any bad/corrupted references during the "validation" process previously mentioned above but cannot really test this on my system since I'm not experiencing any crashes on which to test my theory.)

5) Suggest you try removing the PLIST file as you did before, open the player app, and then try to load a video for playback. Let us know if this generates an new PLIST file and whether or not the video file now plays without crashing the QT X player app.

Hi,

I have the same problem and still haven't found a solution. Every time I try to open Quicktime, I get this message:

"The last time you opened QuickTime Player, it unexpectedly quit while reopening windows. Do you want to try to reopen its windows again?"

Whether I choose "Don't reopen" or "Reopen", the application doesn't work.

Thanks for your help.