"Unfortunately ... has stopped" I'm dealing with a brand-new Samsung Galaxy J5 and various apps and services keep crashing, making the phone all but unusable. It's German but these are the services that are stopping:


Kontaktspeicher angehalten (contact storage)
Kontakte angehalten
Weather Daemon angehalten
Bevorzugte Kontakte angehalten (preferred contacts)
Dual-Uhr angehalten (dual clock)
Uhr angehalten (clock)
Download-Manager angehalten
LogsProvider angehalten
Medienspeicher angehalten (media storage)
Adapt Sound angehalten


Device details:


Samsung Galaxy J5, SM-J500FN
Android v5.1.1
Kernel v3.10.49
Build number LMY48B.J500FNXXU1AOI6
rooted (so I can use Titanium Backup) and running SuperSU; using stock recovery


Based on Google results and site searches here, I have already tried the following without success:


Simply reboot the phone.
Free up some space. (this is an 8GB model and there's at least 1GB still free)
Don't disable any packages. (after the most recent factory reset, the Samsung package disabler isn't even installed.)
In Settings > Application Manager > (app name), clear the cache and clear the app data; repeat for all affected apps; also for the Google Play Store and for Google Play Services; then restart the phone.
Update the applications via the Google Play Store app. (This fails for any and all apps because the Download Manager keeps crashing.)
In Settings > Application Manager > Android System WebView, uninstall updates, then restart the phone. (Version is now reverted to 43.0.2357.121 and was 51.0.2704.81 which I first made a backup of using Titanium Backup.)
Connecting to Samsung Kies software in Windows 7. (This probably fails due to a constant stream of media storage crashes while Kies tries to connect to the phone.)
Wipe the phone using factory reset.


I would like to re-flash the original stock Samsung ROM on the phone so I could return it to real factory default state, but finding the real Samsung ROM is a jungle of Russian and suspicious paid websites that I don't want to dive into, and it's compounded by the multitude of Samsung Galaxy devices. (Update: thanks to Thomas, the link to the original ROMs is here but the downloads only work using IE. I will now try re-flashing the ROM and see if that helps.)

(I'm beginning to regret getting my wife a Samsung rather than a Google Nexus model, but she wanted a physical home button. Why does Samsung manufacture so&nbsp;many different models?)
I recommend you to flash the stock firmware on your device.

As you said you didn't know where to download firmwares for Samsung devices; I'll give you some information.

Personally I always use a site called Sammobile. They host every firmware made by Samsung. The firmwares are 100% stock and won't trigger Knox. You will need to register an account on their website, but it's free.

You can download the firmware for your device here. The firmware can be flashed by using a Windows application called Odin (download link in the guide below).

When the firmware is downloaded, flash it on your phone. Here are the steps:


Extract the firmware
Download Odin 3.11.1.
Extract the Odin zip file.
Open Odin.
Reboot your phone to download mode by holding the home, power and volume down buttons. Release only the power button when at the Samsung logo, and release all of them when you see a green Android robot. Then press volume up to accept the warning and you'll see DOWNLOADING.
Connect the phone to your PC, Odin should now see your device.
Add the firmware file to AP/PDA. (The "not responding" is normal, just wait).
Make sure re-partition is not checked.
Click the start button. The flashing can take some time.



  Note: The firmware will not factory reset your phone, so if your phone is stuck booting, don't worry. Just boot to the recovery mode, do a factory reset and reboot the device.