Check if file exist at screen inizialize. BUG?

I’m refering to Check if file exist - SOLVED
I have made a simple app, one button save a text file, and save to tinyDB the name of file.
When i open the app i call “get value” to read the file name from DB, and then read the file.
If file exist i put the text in a label.
With a second button i made the same (read from file).
If i delete the file manualy, when i start the app don’t have an message error (file not found), but when i push the second button i have it?
The approach to solve the problem proposed to TIMAIL2 is working. But whe think there is a bug.