0x139 BSODs daily when waking up from sleep

Hello and thank you in advance for your assistance, if you have any. I'm open to any suggestions at this point. See my DM files attached at the bottom of this post.

This is my Dell Inspiron 13 7359. The problem started about a week ago; 0x139 KERNEL_SECURITY_CHECK_FAILURE. Happens when I wake the laptop up from sleep (by opening the lid) about 50% of the time. The other 50% of the time, it wakes up without issue.

I tried to analyze the minidumps myself; it confirmed that 0x139 is the issue. However, it found no device driver errors, but maybe I didn't see them--this was my first time using the Debugging Tools.

What I've already attempted to fix it:

1. sfc /scannow (result: no errors found, I believe)
2. Dism /Online /Cleanup-Image /ScanHealth (result: "No component store corruption detected.")
3. Dism /Online /Cleanup-Image /RestoreHealth (result: "The restore operation completed successfully.")
4. Installed all Windows updates (fully patched as of 3/30/17; Version 1607, Build 14393.969)
5. Reinstalled all the latest driver updates from Dell (BIOS updated from 1.14 -> 1.15, Intel Dynamic Platform and Thermal Framework, Intel HID Event Filter Driver, Intel Management Engine Interface Driver, Intel Virtual Buttons Driver, Intel Serial IO Driver, Intel Chipset Driver, Intel 8260/7265/3165/7260/3160 Bluetooth Driver, Intel 8260/7265/7260/3165/3160 WiFi Driver, Dell Foundation Services - Application, Dell QuickSet Application, and Conexant CX20722 Audio Driver).
6. Ran the Power Troubleshooter (fixed my standby time, minimum processor state, and wireless adapter powersavings--did not fix the BSODs).
7. Confirmed latest firmware on my Samsung 840 EVO. I also ran the performance optimization--still getting BSODs.

Does anyone know what could be up? I've uninstalled lots of lingering programs (Inkscape, some old games, etc.), but I can't imagine what I installed in the last week.

My next options: reinstalling the video driver, the SD card reader driver, the Intel Rapid Storage Technology driver, and running MemTest. Will update soon.

Hello :)

I've looked back through your latest crash mini-dumps and every time the process that was running when the crash occurred was Slack. You may be running this as an app for your team communications.

Try closing down this program before you put the laptop to sleep and see if it makes a difference.

Eghad! I missed the notification!

Thank you very much--you were exactly right! I got "adventurous" and had been using the Windows 10 Slack app. A huge mistake; you were SPOT-ON. I uninstalled it and went back to the Win32 Slack app: it's identical, except it doesn't cause BSODs when my laptop wakes up from sleep. I've slept and woke up my computer about 15 times in a row--not a single BSOD. It's a miracle!

Excellent, excellent, excellent find. Thank you very very much, +1

Out of curiosity, what tipped you off that it was Slack? I realized I have a lot of little programs running in the background often (Spotify, Lightshot, Dropbox, etc.). However you figured it out, you nailed it.

Glad this was the answer!

The analysis of the mini-dumps that W10 creates when your system crashes includes details of the process running at the moment of the crash. In your case, every time, it was slack.