A document that looks different after a Mac move may depend on a particular font. Before deleting duplicate entries, identify the font family, the affected document and the copy supplied by the original application or licensed installer.

Keep the document and any legitimate font installation files backed up. A matching family name does not by itself tell you which font copy the project expects. Record the current appearance with a small reference page containing ordinary text, bold text and any special symbols.

Read the validation result

In Font Book on Mac, select the font and choose File, Validate Selection. To inspect a font file before installing it, use File, Validate File. Expand the result to see the reported issue. Apple uses green for passed checks, yellow for warnings and red for failed checks.

A warning is a reason to inspect the details, not an instruction to remove every font in the family. Avoid Remove Checked until you understand which files are selected and have a suitable replacement or recovery route.

For duplicates, choose File, Resolve Duplicates and inspect them manually. Apple identifies the recommended copy as Active and allows a different choice. Automatic resolution can deactivate copies or move them to the Bin according to Font Book settings, so check those settings before considering it.

Prove the document still works

Handle one affected family first. Record which copy you keep and why, then reopen the test document in its usual application. Compare line breaks, page count and representative symbols with the reference.

If the appearance still differs, preserve the evidence and check the application’s font requirements. Repeatedly swapping unrelated fonts makes the original problem harder to trace.

Only extend the change to other families after the small test succeeds. Keep licensed installation media and the original document until the work is accepted. Font validation is useful evidence about a file; it does not guarantee every application will lay out a document identically.

References: Apple: install and validate fonts.