The CD can be installed on as many computer as you the purchaser of the CD own.
With the CD version you can e-file a maximum of 5 returns per e-mail address. After the 5th return, you can still prepare as many returns as you like. However, they will have to be printed, signed and mailed to the IRS. This is not a TurboTax restriction. It's an IRS requirement and federal law.
