When an Android Studio update is posted and you mistakenly click on Ignore This Update how do you apply the update without having to reinstall Android Studio?>
Update
As of the latest version of Android Studio, there is now a Preference in the UI noted in an answer by Yogesh Umesh Vaity
Original Answer
The simple way to revert a mistaken choice is to close Android Studio then edit other.xml file and remove the myIgnoredBuildNumbers option block:
Technically you should edit the size and remove the item in question but after some testing the next time you ignore a build the myIgnoredBuildNumbers block will be rebuilt.
The other.xml file can be found at:
~/Library/Preferences/AndroidStudio/options/other.xml%HOMEPATH%\.AndroidStudio\config\options\other.xml~/.AndroidStudio/config/options/other.xmlThe same can be done in Intellij in the following paths:
~/Library/Preferences/IdeaIC12/options/other.xml%HOMEPATH%\.IdeaIC12\options\other.xmlAs of Android Studio 1.2(possibly earlier), the ignored builds block is defined in updates.xml within the same directory as other.xml