Q: I’ve been using the free Adobe Acrobat Reader DC to fill in and save PDF tax forms on my PC. But when I recently called up a stored tax form, the data I’d filled in appeared for a moment, then disappeared, leaving just a blank tax form. I then called up other tax forms that I’d saved earlier, and found that some still had their data and others did not.

Adobe won’t help me with this problem because I’m using a free app. What’s wrong and what can I do?

— Mike Hess, Monument, Colo.

A: The disappearing tax data problem is caused by the way Adobe PDF files are stored.

While a PDF looks like one continuous document when you view it, it’s actually stored in layers of data so that the file will take up less space on a hard drive or other data storage device.

Occasionally this data layering has an unintended visual effect: When a PDF form is filled out, stored and then opened again, the information that was entered seems to have disappeared — even though it’s still present.

The workaround for this problem is to “flatten” the PDF file, so that it stores all of its data in one layer. Once the layers are gone, you’ll be able to see all the tax information you entered every time the PDF file is opened.

However, this workaround comes with a limitation: Once you’ve flattened a PDF file, you won’t be able to add any more data to it, or to convert it back into a regular PDF file. So, make sure your tax form is complete and accurate before you make the change.

Here are two ways to turn your completed tax form from a normal PDF file into a flattened one:

• In the PDF file, press the CTRL and P keys simultaneously. You’ll then see a box with choices for how to print the file; choose either Adobe PDF or Microsoft PDF as your “printer.” In most cases, this will flatten the PDF file.

• In the PDF file, use the “save as” command to save the tax form as an Adobe PostScript file (which has the suffix “.ps”).

Then use one of several free websites (see tinyurl.com/y9wkhh94 or tinyurl.com/dtb4sneb or tinyurl.com/48s65r7w) to convert the PostScript file into a flattened PDF file.

Contact Steve Alexander at steve.j.alexander@gmail.com. Please include a full name, city and phone number.

Contact Steve Alexander at steve.j.alexander@gmail.com. Please include a full name, city and phone number.