IDE won't launch

Development Tools IDE 1.x
1

Running on Windows 10. Was working this morning and suddenly when I launch the application the splash screen appears and gets to "starting" and then the splash screen disappears and nothing happens. I did an uninstall and reinstall, and still same problem. Ran the arduino_debug.exe and this is what it prints:

Microsoft Windows [Version 10.0.15063]
(c) 2017 Microsoft Corporation. All rights reserved.

c:\Program Files (x86)\Arduino>arduino_debug.exe
Looking for library 'user32'
Adding paths from jna.library.path: null
Trying user32.dll
Found library 'user32' at user32.dll
Looking for library 'shell32'
Adding paths from jna.library.path: null
Trying shell32.dll
Found library 'shell32' at shell32.dll
Looking for library 'Ole32'
Adding paths from jna.library.path: null
Trying Ole32.dll
Found library 'Ole32' at Ole32.dll
Loading configuration...
Initializing packages...
Preparing boards...
Starting...
java.lang.IllegalArgumentException: Font size must be > 0
at org.fife.ui.rtextarea.RTextAreaBase.setFont(RTextAreaBase.java:986)
at org.fife.ui.rsyntaxtextarea.RSyntaxTextArea.setFont(RSyntaxTextArea.java:2510)
at processing.app.EditorTab.applyPreferences(EditorTab.java:322)
at processing.app.EditorTab.(EditorTab.java:110)
at processing.app.Editor.addTab(Editor.java:1672)
at processing.app.Editor.createTabs(Editor.java:1645)
at processing.app.Editor.handleOpenInternal(Editor.java:1944)
at processing.app.Editor.(Editor.java:340)
at processing.app.Base.handleOpen(Base.java:833)
at processing.app.Base.restoreSketches(Base.java:518)
at processing.app.Base.(Base.java:456)
at processing.app.Base.main(Base.java:140)

Any thoughts? Thanks in advance.

2

Solved problem: From another post on the font size error I was directed to go to my windows user directory and in the arduino folder edit preferences.txt. Found the editor.font line had specified font of 0. I had somehow zoomed in on the sketch when I last edited it so that it was so small I couldn't read it. It saves the font setting automatically when you close the sketch. Changed 0 to 12, saved the file and all is well.

3

Note that the same issue will occur again if you use the ctrl+mousewheel keyboard shortcut to shrink the font size to 0. I don't know why anyone would do that but it has happened surprisingly often. The real solution is to just update your IDE version to 1.8.5. This bug only occurs in the outdated Arduino IDE 1.8.4.