The text passed through a system that could not hold the character. It was swapped for a question mark.
Technical note: A question mark usually means the text was converted through an encoding that could not hold the character. It is data loss, not a font problem.Reviewed by CoolSymbol.now Editorial · August 2, 2026What you need to know
A blank rectangle means the font has no picture for a character that is still intact.
The common culprits are a database column that is not UTF-8, a CSV export with the wrong encoding, an email gateway, or an old content system converting on save.
Use UTF-8 everywhere: the database, the connection, the file, the page and the export.
See real examples in technical symbols and math symbols. For the full lesson, read Why Symbols Look Different Across Fonts and Devices.
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This is different from a blank box
A blank rectangle means the font has no picture for a character that is still intact. A question mark usually means the character itself is gone.
Something converted your text to an encoding with no room for it — often Latin-1 or an old Windows code page — and substituted a question mark for anything it could not represent.
- Blank box: character fine, font missing
- Question mark: character replaced, data lost
- Diamond with a question mark: bytes decoded wrongly
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Where it usually happens
The common culprits are a database column that is not UTF-8, a CSV export with the wrong encoding, an email gateway, or an old content system converting on save.
Because the character is already gone, changing the font will not bring it back. You have to fix the encoding and paste the text again.
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The fix
Use UTF-8 everywhere: the database, the connection, the file, the page and the export. Then re-copy the original text from a source that still has it intact.
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Sources and further reading
This answer was reviewed against current Unicode terminology and the practical guidance below.
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