By default IntelliJ IDEA opens the last project when starting.
How to start IntelliJ without opening last project?
On WINDOWS, the path is:
WINDOWS
C:\Users\[USERNAME]\.IntelliJIdea[VERSION]\config\options\ide.general.xml
Then set reopenLastProject to false, i.e.:
reopenLastProject
false
PS: You may have to create the option if it doesn't exist.