Error -50: an unknown error has occurred

Nor can I start the Quicktime program

Can you walk us through what happens when you try to launch the program? (If an error message is involved, let us know what it says.)

It's no consolation but I have the exact same situation.

I have an MP4 file on my desktop. I double click on it and get a dialog box titled "Error" containing the text "Error -50: an unknown error occurred (filename.mp4)" with an OK box.

Click OK and the box goes away and the video doesn't play.

Quicktime doesn't start if I select Quicktime Player from the start menu. I get a busy cursor for a second then nothing. I've uninstalled and reinstalled the latest Quicktime a couple of times with no difference.

Here's some more information that might be relevant.

I uninstall Quicktime. Download the latest 7.5 version and install it. It tells me that it's going to install version 7.50.61.0. I install it and it succeeds.

I go to the Quicktime control panel applet and click on the "About Quicktime..." button on the Register tab. The version number shows up as 7.4.

Hourglass for a second or two, then nothing.

Okay. I'm wondering about whether there's an issue with a firewall setting for QuickTime here. (That can sometimes either stall out or completely abort a QuickTime launch, with no accompanying error messages.)

If that's what is going on, often the QuickTimePlayer.exe process will start when you try to launch QuickTime, and then stay active even though QuickTime isn't launching.

So let's check on that. Restart the PC and then bring up your Task manager. Click on the Processes tab. Now try a QuickTime launch. Does a QuickTimePlayer.exe process appear? If so, does it persist in Task manager, or does it vanish after a second or two?

Here's what I tried:

Installed Quicktime 7.5.
Start Quicktime by clicking on the desktop shortcut.
Use File/Open File then select movie.mp4.
Get the error -50
Click OK, close Quicktime Player
The QuickTimePlayer.exe disappears from the task manager.

Double click the file movie.mp4
QuickTimePlayer.exe appears in the task manager.
The player user interface doesn't appear.
Get the error -50, click OK
The player UI never appears.
QuickTimePlayer.exe stays in the task manager and doesn't get removed.

I tried these tests with the firewall enabled and disabled.

Further to my version testing:
Installing 7.5 doesn't work.
Installing 7.45 doesn't work - I still get -50
If I install 7.4, it works properly.

I believe it's related to the fact that the Control Panel applet always reports version 7.4 regardless of the actual installed version. I get the feeling that there are components of 7.4 being left behind after an uninstall but I don't know what they are or where they're living. The Quicktime install directory gets deleted but there may be DLLs left in windows\system32 or elsewhere.

Sorry no answer - I have the same problem though

Quicktime won't open ANY files (not even .mov or .m4a or anything)

I get the Error 50 message and QuicktimePlayer.exe stays in the Task Manager.

Please someone from Apple help us! It's so annoying - especially being obsessed with my ipod and not being able to listen to anything.

QuickTime Player ... Version 7.5 (861) ... Quicktime Version 7.1.3

Have you got two different versions of QuickTime installed on the PC at the same time, Yoke?

(Having two different versions installed at the same time can cause problems ... which is why under normal circumstances a QuickTime 7.5 install would uninstall any previous versions, or at least attempt to do so.)

Do you have anything else installed on the PC that might have installed older QuickTime componentry on the PC? (Say, old versions of ACE or K-Lite Mega Codec packs, old versions of the programs QT Alternative, QT Lite or Storm Codec, or some variety of media converter that can convert files to and from QT-readable formats?)

Same problem. I just encoded some Quick Time files and they will not play at all. The QT Player seems to work but it will not play any files.

Could this be some strange bug with Vista SP1 or something..

Man it was tuned with I bought this thing...lol

I had this problem (Error -50) on CD's I bought to accompany a math textbook. The publisher supplied the following helpful and very complete answer.

But first a question/comment for Apple: Many of us have video products which are incompatible with the newer versions of QuickTime. When will you fix QuickTime so it is backward compatible? Or shall we simply turn off Apple Updates forever?

Advice from textbook publisher:

Recently, Apple updated the way that QuickTime handles certain file types. Due to this, some users are experiencing difficulties viewing QuickTime content within their course or from CD-ROM. Below are the instructions to uninstall your current version of QuickTime (if you have it installed) and download and install a slightly earlier version that does work with our media files.

You must first uninstall version 7.2 of QuickTime from your computer before you try to install this 7.1.6 version of QuickTime. You do this from the Add/Remove Programs option in your Control Panel (In Windows XP go to Start Button, click Control Panel then Add/Remove Programs. In Windows Vista go to Start Button, Click Control Panel, then Programs and Features.) Once you have removed the newer version, open a browser window and go to the following URL:

http://www.apple.com/support/downloads/quicktime716forwindows.html

There is a download link that says 19.1mb and that is the file you will need to download the slightly older version of QuickTime.

Once you uninstall version 7.2 of QuickTime and get the 7.1.6 version installed, please check if your videos will play from the CD (or local hard drive.) If they do, then all is ok and you should be set. If videos do not play, follow the instructions below for recommended changes to the settings of your QuickTime.

At any point in the future if you are asked to upgrade your version of QuickTime to a newer version please don't upgrade. Upgrading to the newest version will generally give you the same problems playing videos that you had before.

============================

1. Open the Control Panel by clicking on your Start button and then on the Control Panel icon and click on Switch to Classic View that is on the left hand side of the window (if it says Switch to Classic View). Double-click on the blue QuickTime icon to open the QuickTime settings window.

2. Go to the Audio tab. In the Sound Out section set the Rate to: 32 kHz, the Size to: 16 bit, and the Channels to: Stereo (L R)

3. Select the Browser tab and make sure that the Play movies automatically box is checked, then click on the MIME Settings… button at the bottom. In the MIME Types window that opens, click the Use Defaults button and then click OK.

4. Select the Streaming tab and choose 512 kbps DSL/Cable in the drop-down menu under Streaming Speed. Make sure there is a checkmark next to Enable Instant-On and the indicator should be above Immediately under Play Streams.

5. Select the File Types tab and click on the Use Defaults button.

6. Select the Advanced Tab. If Transport Setup is set up to Automatic, click the down arrow in the drop-down menu and choose custom. For Transport Protocol choose HTTP, and for Port ID: 80. Click the OK button. Next, click the Empty Cache button. Under the Video section, check the Safe mode (GDI only) radio button. Click the Empty Cache button.

7. Click the Apply button on the lower right. Next, click OK. Finally, close the Control Panel.