[Sprint HTC One (M8)] cytherian:
Phone: HTC One M8 HK modelid: 0P6B70000, cidnum: SPCS_004; S-ON; Bootloader 3.19; Rooted; TWRP 3.2

ROM: Stock, updated 6.20.654.3

I wanted to utilize Titanium Backup but I discovered that I need to have BusyBox installed. I have TWRP and root. So I went to install BusyBox and ran into all kinds of problems.

First, there are several busybox installer apps out there. I tried a few and although the app would install, the install busybox function wouldn't work. I'd click "install" and then it would sit there doing nothing. In a few moments, a cascade of Google and HTC service apps would start to crash. A real mess. I would reboot and try again... same thing. Cleared cache of Google and HTC services... no difference.

During the process and chaos of notification messages popping up about this service or that service stopping, I caught notice of a SuperSU receiving a request to grant permissions from BusyBox. But by the time I could get access to grant it (clearing away other notifications), the busybox installation would have already aborted.

Older posts about this problem claimed "busybox on rails" would fix this. I tried and it didn't. I then tried the Stericson busybox. Same service crashes started happening once again. So the problem appeared to be some peculiar delay, where the SU request from an app is not getting to SuperSU in time for being granted permission. With Stericson busybox, I was able to finally grant access in SuperSU, although it had aborted. With the grant already done, restarting the Stericson busybox install allowed it to proceed to the next step of getting the Smart Installer loaded. During that process, I kept having to clear away notifications of services and apps crashing. That kept continuing as busybox actually installed. So I kept closing notifications until busybox finished installing. The Root# app verified busybox is installed correctly. The service crashes stopped. Opening the busybox installer app works fine now.

I eventually discovered the install issue... the SuperSU app has a "tapjacking" feature, whereby an su permission request dialog won't respond to input while obscured by other window/overlay. I found that Titanium Backup Pro wouldn't recognize busybox being installed, as SuperSU hadn't received any request from Titanium. I'm guessing that this caused a clash at a fundamental level, to cause services to crash? I unchecked the tapjacking option and finally I could grant Titanium Backup su permission. And now I'm able to use TBP (Titanium Backup Pro). However... it's not working quite right. When I attempt to backup user apps, some will be backed up but others are extremely slow or fail. Busybox Free 55 (Stericson) causes TBP to completely crash. OK, so I went to skip backing up that app. I then started to do one app at a time. Some apps would backup quickly, while others take an extraordinarily long period of time. Cardboard 1.8 was extremely, painfully slow (which is 456Mb). I hadn't used that app in a long while, so I just deleted it. But then when attempting to backup Excel (220mb), TBP stalled on that app... eventually completed it. Backup just seems very slow. But I can live with that as long as backups have integrity.

So I'm feeling like something might not be quite right with my system. Everything generally seems to be fine. With tapjacking disabled, SuperSU is fielding requests without services crashing. The only really bizarre thing is that TBP is simply unable to backup busybox. Anytime I try to do it, TBP crashes. Very strange. Do I need to stop and disable it first?