When I open a pdf file it will sometimes only shows small boxes in place of characters.
If I open it with another program, such as Foxit, it opens correctly.
How can I fix this in Acrobat?
Sorry for the delay in response to your query and apologize for the inconvenience caused. Please check for any updates from Help Menu>Check for updates. You may also try to uninstall and reinstall the Acrobat.
Note: The above-mentioned steps may or may not work as Acrobat 8 is declared as an End of Life and Support product. The support is limited, for more information, please refer to End of support | Reader 9 and Acrobat 9 (and earlier)
If the issue persists, please share the following details:
Hope this helps, and let us know how it goes.