I’ve encountered multiple occasions where the text content in an Adobe PDF file disappears out of blue without reason. It happens the most in fillable forms where the text you just entered disappears on you right after you hit that Save button. Other times, they disappear after I made some changes to the PDF document. Very puzzling sometimes.
After some researching, it appears that the use of layers and layers with transparency in PDF might be the reason behind this mysteries behave. Thanks to this post.
While correcting the original PDFs might not be an option, you can try to flattening the layers into one layer in PDF to fix the problem.
Here are two ways of doing it:
Print to PDF
Open PDF file and press Ctrl+P to bring up the Print dialog box. Then select Adobe PDF or Microsoft PDF as the printer. This will regenerate another version of PDF file with the default setting. In most cases, this will merge all the layers into one.
If this doesn’t work, try the next one.
Use Save As… in PDF, select PostScript as the
Once saved, double-clicking the .ps file opens it in Adobe Distiller that automatically converts it to a PDF file that is flattened with only one layer visible.
That’s about it. If you’ve had the same problem before hope this helps.