When a PDF is created, if the creator does not check "Embed Fonts," the file only references the font name. When you open it, your operating system looks for "F1 Medium" but cannot find it. The PDF reader (like Adobe Acrobat or Illustrator) then swaps the missing font with a default placeholder and gives it the temporary handle: CIDFont+F1 .
: Used primarily to support large and complex character sets (like Asian languages) or to subset fonts to reduce PDF file size. cid font f1 family hot
Community members suggest several workarounds for these issues: When a PDF is created, if the creator