For just the reasons you mention you should always print a complete copy of your tax returns (all forms, schedules and worksheets) to be tucked away with supporting documentation - receipts for charitable donations with worksheets showing how amount was determined, details of security sales, particularly how you've determined basis, all "informational" returns like 1099's, Schedule K-1's, etc. You just can't depend on being able to open a file several years down the road.
Tom Young
