Maybe it's not the pop up, but the reminder that you hate? Your friend is truly offline.

Maybe you aren't ready to delete it. But maybe you should, and try to remember him without that "reminder."

The grieving process is different for everyone.
I have a voice message/ phone answerer at home. Everytime someone calls and leaves a message, I have to skip through the ones I've left on there. One's from my mom, now passed a year, asking for me to come help her. Another is from one of my sisters, who breaks down sobbing, as we were trying to figure out what was best for mom and to try to keep her alive. Like you, I hate being reminded, but I just can't let go yet. Two others are from mom's best friend...

Be gentle with yourself.