[One (M8) Q&A, Help & Troubleshooting] thebobmannh:
Well, I fully wiped my SD card and did an RUU. Haven't had a crash yet but still see this error in my logcat :

E/Vold ( 382): Failed to find mounted volume for /storage/ext_sd/Android/data/com.google.android.youtube/cache

For a few apps (these are all system / default apps, I haven't installed anything yet).

And also a few other errors that just shouldn't be there for a clean install

I/ActivityManager( 895): Start proc com.android.cellbroadcastreceiver for broadcast com.android.cellbroadcastreceiver/.CellBroadcastReceiver: pid=2959 uid=10003 gids={50003, 9997} abi=armeabi-v7a
I/ActivityManager( 895): Killing 2504:com.htc.sense.hsp/u0a14 (adj 15): empty #17
I/ActivityManager( 895): Recipient 2504
W/BroadcastQueue( 895): Exception when sending broadcast to ComponentInfo{com.htc.sense.hsp/com.htc.sense.hsp.weather.provider.data.Receiver}
W/BroadcastQueue( 895): android.os.DeadObjectException
W/BroadcastQueue( 895):	at android.os.BinderProxy.transactNative(Native Method)
W/BroadcastQueue( 895):	at android.os.BinderProxy.transact(Binder.java)
W/BroadcastQueue( 895):	at android.app.ApplicationThreadProxy.scheduleReceiver(ApplicationThreadNative.java)
W/BroadcastQueue( 895):	at com.android.server.am.BroadcastQueue.processCurBroadcastLocked(BroadcastQueue.java)
W/BroadcastQueue( 895):	at com.android.server.am.BroadcastQueue.processNextBroadcast(BroadcastQueue.java)
W/BroadcastQueue( 895):	at com.android.server.am.ActivityManagerService.finishReceiver(ActivityManagerService.java)
W/BroadcastQueue( 895):	at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java)
W/BroadcastQueue( 895):	at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java)
W/BroadcastQueue( 895):	at android.os.Binder.execTransact(Binder.java)
W/libprocessgroup( 895): failed to open /acct/uid_10014/pid_2504/cgroup.procs: No such file or directory
I/ActivityManager( 895): Start proc com.htc.sense.hsp for broadcast com.htc.sense.hsp/.weather.provider.data.Receiver: pid=2991 uid=10014 gids={50014, 9997, 1023, 3003} abi=armeabi-v7a
W/ActivityManager( 895): Spurious death for ProcessRecord{ee7324c 2991:com.htc.sense.hsp/u0a14}, curProc for 2504: null
I/ActivityManager( 895): Start proc com.google.android.partnersetup for broadcast com.google.android.partnersetup/.PhoneStateReceiver: pid=3030 uid=10013 gids={50013, 9997, 3003} abi=armeabi-v7a
I/ActivityManager( 895): Killing 2526:com.android.managedprovisioning/u0a15 (adj 15): empty #17
I/ActivityManager( 895): Recipient 2526
W/libprocessgroup( 895): failed to open /acct/uid_10015/pid_2526/cgroup.procs: No such file or directory
I/ActivityManager( 895): Start proc eu.chainfire.supersu for broadcast eu.chainfire.supersu/.UserPresentReceiver: pid=3054 uid=10050 gids={50050, 9997} abi=armeabi-v7a
I/ActivityManager( 895): Killing 2548:com.ota.updates/u0a17 (adj 15): empty #17
I/ActivityManager( 895): Recipient 2548
W/libprocessgroup( 895): failed to open /acct/uid_10017/pid_2548/cgroup.procs: No such file or directory
I/ActivityManager( 895): Killing 2088:com.google.android.apps.walletnfcrel/u0a26 (adj 15): empty #17
I/ActivityManager( 895): Recipient 2088
W/libprocessgroup( 895): failed to open /acct/uid_10026/pid_2088/cgroup.procs: No such file or directory

Hopefully these are innocuous or at this point I have to suspect a hardware problem.