File | Settings | Appearance and Behavior | System Settings for Windows and Linux IntelliJ IDEA | Preferences | Appearance and Behavior | System Settings for macOS Ctrl+Alt+S
Use this page to configure general behavior of IntelliJ IDEA.
Reopen last project on startup
Select this checkbox to have IntelliJ IDEA re-open the last opened project on startup.
Confirm application exit
Select this checkbox to have a warning message displayed when you attempt to close IntelliJ IDEA.
Open project in a new window
Click this radio button to always open a new project in a new window.
Open project in the same window
Click this radio button to always close the current project, and reuse the same window.
Confirm window to open project in
Click this radio button to have IntelliJ IDEA ask you whether you want to open a new project in the same frame, or in a new one.
Synchronize files on frame or editor tab activation
If this checkbox is selected, all the files that were changed externally are reloaded from disk when you switch to IntelliJ IDEA from a different application, or when you you switch to their editor tab.
Save files on frame deactivation
If this checkbox is selected, all modified files are auto saved when you switch from IntelliJ IDEA to a different application.
Use "safe write" (save changes to a temporary file first)
If this checkbox is selected, a changed file is first saved in a temporary file. If the save operation succeeds, the file being saved is replaced with the saved file. (Technically, the original file is deleted and the temporary file is renamed.) Also, the ownership of such file changes.
If this checkbox is not selected, the ownership of a file does not change, but all the advantages of safe write will be lost.
Support screen readers (requires restart)
On Closing Tool Windows with Running Process
If this option is selected, the running process disconnects and terminates silently.
Disconnect (if available)
If this option is selected, the running process is disconnected.
If this option is selected, the dialog box shows up: