osX and running different versions of one program

in macOS edited January 2014
Hi, all.

I'm doing some web design and I want to have all my browsers running at once so I can compare the way they are rendering the pages.

The problem is that when I try to launch the older classic versions (netscape 4.7, IE 5.0) while I have the newest ones running in OS 10.2 I get a message that asks me if I want to quit the newer versions and start the old ones.

This very annoying -- classic Netscape 4.7 and osx netscape 7 are not even the same program.

Is there some way around this aggravating limit to the number of instances of a program you can have running at once?

I just can't understand why they would stop you form doing this.


  • Reply 1 of 4
    resres Posts: 711member
    This is interesting -- If I start up classic first, I can get the older versions of the browsers to open. So that solves my problem.

    But is there a way to force OSX to allow you to run multiple instances of the same program?
  • Reply 2 of 4
    Nearly all apps work just fine when you have multiple instances or versions of them.

    Netscape, on the other hand, is *specifically* written so that you can't so this. I think it's because of some paranoid security issues. I don't know of any way around it except what you mentioned in your second post.
  • Reply 3 of 4
    There are potential conflicts,such as if two versions of the same app try to access the same preferences file at the same time.
  • Reply 4 of 4
    Meteorologist has the method to make cocoa apps run like that and use different preferences files:

    From the Multiple_Meteos_Hack.rtdf

    Multiple Instances of Meteo Hack


    When I was designing meteo, I had no intentions on displaying weather info for multiple cities at the same time in the menu bar. If I had thought it out before, you wouldn't have to do the described hack below to get two instances of Meteo running with each displaying different city weather info. Here's the hack:

    1. Locate your copy of Meteorologist

    2. Make a duplicate of Meteo by dragging the app and holding down the option key and letting go, or by selecting Meteo and performing an Apple-D.

    3. Rename the copy to something useful, like Meteorologist2.

    4. Right click or control-click on the copy of Meteo and select "Show Package Contents."

    5. In the finder window that opens, go into the Contents folder.

    6. In the Contents folder, open up the Info.plist file in TextEdit. If double-clicking on the plist doesn't automatically open the file in TextEdit, right click (or control click) the file, go to "Open With" and choose "Other", selecting Text Edit from the open panel that is displayed.

    7. In the Info.plist file, look through the mess until you see CFBundleExecutbale. Right below that should be the word Meteorologist. Change that to whatever you named your copy of Meteo. Save the file and quit out of text edit.

    8. Finally, go back to the Finder window that has the Info.plist file. Navigate into the MacOS folder and rename the file called Meteorologist to whatever you named your copy of Meteo.

    9. You're done! Now you have two copies of Meteo that can run in the menu bar (or dock) simultaneously and have different preferences.
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