I can't get the snapshots. I tried redownloading the launcher but it didn't work. The launcher bugs out and can't use the snapshots. Please fix!
EDIT: I have found a workaround. I changed the 15w44a version type to "release", which fixes it for now.

Here's the output:
[
[17:07:08 INFO]: Minecraft Launcher 1.6.48 (through bootstrap 100) started on windows...
[17:07:08 INFO]: Current time is Oct 28, 2015 5:07:08 PM
[17:07:08 INFO]: System.getProperty('os.name') == 'Windows 7'
[17:07:08 INFO]: System.getProperty('os.version') == '6.1'
[17:07:08 INFO]: System.getProperty('os.arch') == 'x86'
[17:07:08 INFO]: System.getProperty('java.version') == '1.8.0_25'
[17:07:08 INFO]: System.getProperty('java.vendor') == 'Oracle Corporation'
[17:07:08 INFO]: System.getProperty('sun.arch.data.model') == '32'
[17:07:08 INFO]: proxy == DIRECT
[17:07:09 INFO]: JFX is already initialized
[17:07:11 INFO]: Refreshing local version list...
[17:07:15 INFO]: Refreshing remote version list...
[17:07:19 INFO]: Refresh complete.
[17:07:20 INFO]: Loaded 2 profile(s); selected 'RosalinaFan573'
[17:07:20 INFO]: Refreshing auth...
[17:07:20 INFO]: Logging in with access token
[17:07:23 FATAL]: Unhandled exception in thread Thread[AWT-EventQueue-0,6,main]
java.lang.IllegalArgumentException: Version cannot be null
at net.minecraft.launcher.updater.VersionList.getCompleteVersion(VersionList.java:61) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:210) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.CompleteMinecraftVersion.resolve(CompleteMinecraftVersion.java:253) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.CompleteMinecraftVersion.resolve(CompleteMinecraftVersion.java:240) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.MinecraftVersionManager.getVersionSyncInfo(MinecraftVersionManager.java:169) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.MinecraftVersionManager.getVersions(MinecraftVersionManager.java:103) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.game.GameLaunchDispatcher.getStatus(GameLaunchDispatcher.java:35) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.ui.bottombar.PlayButtonPanel.checkState(PlayButtonPanel.java:94) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.ui.bottombar.PlayButtonPanel.onProfilesRefreshed(PlayButtonPanel.java:90) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.profile.ProfileManager.fireRefreshEvent(ProfileManager.java:83) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.profile.ProfileManager.setSelectedProfile(ProfileManager.java:125) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.ui.bottombar.ProfileSelectionPanel.itemStateChanged(ProfileSelectionPanel.java:121) ~[launcher.jar:1.6.48]
at javax.swing.JComboBox.fireItemStateChanged(JComboBox.java:1223) ~[?:1.8.0_25]
at javax.swing.JComboBox.selectedItemChanged(JComboBox.java:1280) ~[?:1.8.0_25]
at javax.swing.JComboBox.contentsChanged(JComboBox.java:1329) ~[?:1.8.0_25]
at javax.swing.AbstractListModel.fireContentsChanged(AbstractListModel.java:118) ~[?:1.8.0_25]
at javax.swing.DefaultComboBoxModel.setSelectedItem(DefaultComboBoxModel.java:93) ~[?:1.8.0_25]
at javax.swing.JComboBox.setSelectedItem(JComboBox.java:576) ~[?:1.8.0_25]
at javax.swing.JComboBox.setSelectedIndex(JComboBox.java:622) ~[?:1.8.0_25]
at javax.swing.plaf.basic.BasicComboPopup$Handler.mouseReleased(BasicComboPopup.java:834) ~[?:1.8.0_25]
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:290) ~[?:1.8.0_25]
at java.awt.Component.processMouseEvent(Component.java:6525) ~[?:1.8.0_25]
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) ~[?:1.8.0_25]
at javax.swing.plaf.basic.BasicComboPopup$1.processMouseEvent(BasicComboPopup.java:498) ~[?:1.8.0_25]
at java.awt.Component.processEvent(Component.java:6290) ~[?:1.8.0_25]
at java.awt.Container.processEvent(Container.java:2234) ~[?:1.8.0_25]
at java.awt.Component.dispatchEventImpl(Component.java:4881) ~[?:1.8.0_25]
at java.awt.Container.dispatchEventImpl(Container.java:2292) ~[?:1.8.0_25]
at java.awt.Component.dispatchEvent(Component.java:4703) ~[?:1.8.0_25]
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898) ~[?:1.8.0_25]
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533) ~[?:1.8.0_25]
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462) ~[?:1.8.0_25]
at java.awt.Container.dispatchEventImpl(Container.java:2278) ~[?:1.8.0_25]
at java.awt.Window.dispatchEventImpl(Window.java:2739) ~[?:1.8.0_25]
at java.awt.Component.dispatchEvent(Component.java:4703) ~[?:1.8.0_25]
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746) ~[?:1.8.0_25]
at java.awt.EventQueue.access$400(EventQueue.java:97) ~[?:1.8.0_25]
at java.awt.EventQueue$3.run(EventQueue.java:697) ~[?:1.8.0_25]
at java.awt.EventQueue$3.run(EventQueue.java:691) ~[?:1.8.0_25]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_25]
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) ~[?:1.8.0_25]
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86) ~[?:1.8.0_25]
at java.awt.EventQueue$4.run(EventQueue.java:719) ~[?:1.8.0_25]
at java.awt.EventQueue$4.run(EventQueue.java:717) ~[?:1.8.0_25]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_25]
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) ~[?:1.8.0_25]
at java.awt.EventQueue.dispatchEvent(EventQueue.java:716) ~[?:1.8.0_25]
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) [?:1.8.0_25]
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82) [?:1.8.0_25]
[17:07:23 FATAL]: Unhandled exception in thread Thread[AWT-EventQueue-0,6,main]
java.lang.IllegalArgumentException: Version cannot be null
at net.minecraft.launcher.updater.VersionList.getCompleteVersion(VersionList.java:61) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:210) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.CompleteMinecraftVersion.resolve(CompleteMinecraftVersion.java:253) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.CompleteMinecraftVersion.resolve(CompleteMinecraftVersion.java:240) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.MinecraftVersionManager.getVersionSyncInfo(MinecraftVersionManager.java:169) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.updater.MinecraftVersionManager.getVersions(MinecraftVersionManager.java:103) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.ui.bottombar.PlayerInfoPanel.checkState(PlayerInfoPanel.java:96) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.ui.bottombar.PlayerInfoPanel$2.run(PlayerInfoPanel.java:78) ~[launcher.jar:1.6.48]
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311) ~[?:1.8.0_25]
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:744) ~[?:1.8.0_25]
at java.awt.EventQueue.access$400(EventQueue.java:97) ~[?:1.8.0_25]
at java.awt.EventQueue$3.run(EventQueue.java:697) ~[?:1.8.0_25]
at java.awt.EventQueue$3.run(EventQueue.java:691) ~[?:1.8.0_25]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_25]
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) ~[?:1.8.0_25]
at java.awt.EventQueue.dispatchEvent(EventQueue.java:714) ~[?:1.8.0_25]
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) [?:1.8.0_25]
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) [?:1.8.0_25]
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82) [?:1.8.0_25]
]