You can use the Preflight tool to fix many errors in a document. To do this, you add error corrections, called fixups, to a profile. The fixup automatically corrects the problem, if possible, or provides information so that you can correct the problem in the source file. A profile with a fixup has the gray wrench icon next to it. An outline of a wrench means that no fixups are associated with the profile.
Preflight includes several predefined fixups that you can add to a profile. These cover a broad range of errors that affect color, fonts, images, print production, compliance with international standards like PDF/X and PDF/A, and other areas. Preflight also includes a toolkit for creating your own fixups.
For example, fixups can perform the following actions to correct errors:
Convert color spaces, just as the Convert Color feature does.
Repair documents and eliminate unneeded content to reduce file size, just as PDF Optimizer does.
Convert the PDF to a different version.
Widen hairlines.
Flatten transparency.
Remove objects outside the trim and bleed box.
Prepare the PDF for PDF/X or PDF/A conversions.
Set document information.