Arduino IDE 1.8.4 won't start after using keyboard shortcut to set font size to 0

[720candy]

I can't install Arduino program in my MacBook....At first, I can use this program very well.... suddenly it doesn't work and it show its opening screen like this......then this screen disappear...

install Arduino --> pop up this screen --> disappear this screen --> doesn't work program...
pls help me.........

[facchinm]

Hi @720candy ,
can you try to check if the problem solves following these instructions? #6359 (comment) .
If it doesn't, try running it from the command line to get the whole output.

• launch a terminal
• drag the arduino app in it
• add /Contents/MacOS/Arduino at the end (so you get something like /Users/yourname/Downloads/Arduino.app/Contents/MacOS/Arduino
• press Enter to launch it
• copy the error code here

[720candy]

Thank U command my script! @facchinm

my error code ------

Last login: Fri Sep 8 22:02:18 on ttys000
parkjungui-MacBook-Pro:~ parkjungyeon$ /Users/parkjungyeon/Desktop/Arduino.app/Contents/MacOS/Arduino ; exit;
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.handleOpen(Base.java:819)
at processing.app.Base.handleOpen(Base.java:815)
at processing.app.Base.handleNew(Base.java:754)
at processing.app.Base.(Base.java:460)
at processing.app.Base.main(Base.java:140)
logout
Saving session...
...copying shared history...
...saving history...truncating history files...
...completed.

[facchinm]

Ok, so it's a duplicate of #6359 (comment) where you will find a fix described.

You can find the preferences.txt file in /Users/yourusername/Library/Arduino15 folder (Library is hidden, you can reach it by selecting Go to... on Finder and simply writing Library in there)

This issue has already been fixed(5427f94) in the hourly build and you can solve the problem by using that version of the Arduino IDE but please be aware that it is primarily intended for beta testing.