If you opened pack a first and then try launching pack b it's not able to load up Minecraft about ftblaunch HOT 6 CLOSED

Works for me
Win 7
Java 7

from ftblaunch.

on mac it wont work

loading modpack information...
http://repo.creeperhost.net/direct/FTB2/17ac3bb78f1638a8db7b0b73223c34ee/modpacks.xml
http://repo.creeperhost.net/direct/FTB2/17ac3bb78f1638a8db7b0b73223c34ee/logo_ftb.png
http://repo.creeperhost.net/direct/FTB2/17ac3bb78f1638a8db7b0b73223c34ee/FTBA.zip
http://repo.creeperhost.net/direct/FTB2/17ac3bb78f1638a8db7b0b73223c34ee/splash_FTBa.png
http://repo.creeperhost.net/direct/FTB2/17ac3bb78f1638a8db7b0b73223c34ee/logo_ftb.png
http://repo.creeperhost.net/direct/FTB2/17ac3bb78f1638a8db7b0b73223c34ee/FTBB.zip
http://repo.creeperhost.net/direct/FTB2/17ac3bb78f1638a8db7b0b73223c34ee/splash_FTBb.png
java.io.FileNotFoundException: /Users/marcussooter/Downloads/logindata (No such file or directory)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.(FileInputStream.java:138)
at java.io.FileReader.(FileReader.java:72)
at net.ftb.data.UserManager.read(UserManager.java:93)
at net.ftb.gui.LaunchFrame.(LaunchFrame.java:265)
at net.ftb.gui.LaunchFrame$1.run(LaunchFrame.java:223)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:701)
at java.awt.EventQueue.access$000(EventQueue.java:102)
at java.awt.EventQueue$3.run(EventQueue.java:662)
at java.awt.EventQueue$3.run(EventQueue.java:660)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:671)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
Error loading login data
adding pack 0
adding pack 1
Logging in...

Login complete.
Loading jars...
Loading URL: file:/Users/marcussooter/Downloads/FTBB/.minecraft/bin/minecraftforge.zip
Loading URL: file:/Users/marcussooter/Downloads/FTBB/.minecraft/bin/minecraft.jar
Loading URL: file:/Users/marcussooter/Downloads/FTBB/.minecraft/bin/lwjgl.jar
Loading URL: file:/Users/marcussooter/Downloads/FTBB/.minecraft/bin/lwjgl_util.jar
Loading URL: file:/Users/marcussooter/Downloads/FTBB/.minecraft/bin/jinput.jar
Loading natives...
java.lang.ClassNotFoundException: net.minecraft.client.Minecraft
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at net.ftb.gui.LaunchFrame.launchMinecraft(LaunchFrame.java:837)
at net.ftb.gui.LaunchFrame.runGameUpdater(LaunchFrame.java:715)
at net.ftb.gui.LaunchFrame$8.done(LaunchFrame.java:645)
at javax.swing.SwingWorker$5.run(SwingWorker.java:737)
at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.run(SwingWorker.java:832)
at sun.swing.AccumulativeRunnable.run(AccumulativeRunnable.java:112)
at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.actionPerformed(SwingWorker.java:842)
at javax.swing.Timer.fireActionPerformed(Timer.java:312)
at javax.swing.Timer$DoPostEvent.run(Timer.java:244)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:701)
at java.awt.EventQueue.access$000(EventQueue.java:102)
at java.awt.EventQueue$3.run(EventQueue.java:662)
at java.awt.EventQueue$3.run(EventQueue.java:660)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:671)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)

from ftblaunch.

I suspect this is the servers being overloaded though I will look into that.

from ftblaunch.

Yea, I got the same issue.

http://pastebin.com/e9R0N3U5

from ftblaunch.

So an update on all of this. After deleting all the files within the folder containing the launcher jar, I was able to install and run Pack A, then close and install and run Pack B. Not sure if there is some data saved somewhere saying that the pack was downloaded when it wasn't (due to connection overload) or something of that nature. But this issue is from the files (/FTBB/) not existing when the launcher thinks they do.

Maybe add in checks for files existing upon launching the game? Took a look through the source and still attempting understand the file/method call structure, but I didn't see any checks for if the files existed upon launching of the game.

from ftblaunch.

Should be fixed in latest build. Feel free to make a bug report if you're getting the same issue.

from ftblaunch.