This often happens when Ubuntu is turned on.

Why

Ubuntu desktop version is pre installed with app, which is an error collection system. It collects software crashes, unhandled exceptions and other information, including program bugs, and generates crash reports for debugging purposes. When an application crashes or a bug occurs, the app will alert the user through a pop-up window and ask the user whether to submit a crash report

“Sorry, the application XXX has closed unexpectedly.”
“sorry, the application XXX has closed unexpectedly.”  
“Sorry, Ubuntu XX.XX Has experienced an internal error.
“sorry, Ubuntu XX.XX An internal error has occurred. ”
“system program problem detected.”
“system program problem detected.”

The actual situation is not that Ubuntu is prone to internal errors, but that once the program crashes once, a. Crash file will be generated to record the crash information, which is stored in the directory:

/var/crash/ 

As long as you don’t deal with it, every time you turn on it, you will be prompted with an error. That is to say: the error report is not necessarily something wrong, but there have been errors, and you did not deal with them. Usually, go to the/var/crash/directory to view the crash file. If it’s not a big problem (usually no big problem), delete the crash file in the directory, and then no more errors will be reported.

Solution:

Error report for permanently closing the app
to permanently close the app, edit/etc/default/APP and modify the following parameters

enabled=0 

Restart your Ubuntu system, and the app will shut down automatically
if you never use it again, there is a simple way to remove it completely

$ sudo apt-get purge apport

Even if I removed the app directly, there was no problem.