: In Adobe Acrobat, press Ctrl+D (or Cmd+D ) and go to the Fonts tab. This list may show the "Actual Font" name next to the CID placeholder, telling you exactly which font you need to install. Why This Happens
If you want, I can:
If you absolutely need legacy files, search for (download from GitHub or Adobe Archive). Rename them carefully: Cid Font F1 F2 F3 Download
Click on in the top menu bar, then select Properties (or press Ctrl + D / Cmd + D ). Navigate to the Fonts tab in the window that appears. : In Adobe Acrobat, press Ctrl+D (or Cmd+D