The Lapsed Donor report helps in finding people that used to donate, but have stopped.
From the left navigation select Reporting > Library. under the "Contribution" in the reporting library select "Lapsed Donors".
(pop up after selected)
Data Source: This reports feature a "Data Source" which lets you control exactly who should be considered in the results.
By default, only unarchived profiles are included, but you can also set a custom criteria which uses any saved search in the People Query Builder. In this way, you can limit the results to only the individuals you are interested in reporting (i.e. members of a particular group, specific record types, etc.)
Type: The results return family units by default, though individual donors can be set if needed.
The parameters Donated At Least, Within, But Not Within, and Format can be adjusted as desired.
Results appear directly on screen by default. This lets you interact with the report and easily visit profiles if desired. The actions menu also lets you email and send a text message to individuals in the results. You can also choose to add them to a particular group or workflow process (if available and access rights allow).