'Optimizing app 1 of 1' on boot

[shmul]

When my z5 compact becomes a bit laggy, I restart it and it gets better

BUT

whenever I do that (laggy phone>restart) I get a message on boot saying that android is optimizing ONE app.

I assume that there's one app that making my device laggy and that it's the one that's being optimized on the following boot.

How can I find out which app it is?

I'd like to try to remove it to see if it solves the lag in the phone.

Thanks.

[Qatrium]

@shmul

It's really hard to know, you'll have to do either one of the following:

- Uninstall apps one by one (starting with latest added ones) and restart between to check wich one.

- Perform a software repair using Xperia Companion and install app that are optimized for Android M, or at least recently updated by their developers.

I prefer option 2.

[heyitsme03]

My sister's phone is sony xperia xa ultra, she often gets this kind of message when restarting her phone. "Optiming app 1 of 1" what she did was she uninstalled the recent downloaded apps one by one. When she restarted it again, the message is now gone.