From my duplicate bug #372460: This is probably due to this absurdly small timeout in update-notifier-0.78/src/update-notifier.c:
#define TIMEOUT_APT_RUN 120 /* 120 sec */
Though even if the timeout expires, update-notifier should check to see whether a package manager is still working, instead of advising the user to immediately reboot which would forcefully abort the operation in progress.
From my duplicate bug #372460: This is probably due to this absurdly small timeout in update- notifier- 0.78/src/ update- notifier. c:
#define TIMEOUT_APT_RUN 120 /* 120 sec */
Though even if the timeout expires, update-notifier should check to see whether a package manager is still working, instead of advising the user to immediately reboot which would forcefully abort the operation in progress.