How to figure out why NinjaTrader is crashing at startup

If NinjaTrader is crashing at startup, there are a few things to try.  If these don't work, then contact NT support as they will likely have other ideas (and perhaps better suggestions) to try - though they often just stop helping when 3rd party indicators are involved.  That may depend on who you get to help you from their support team.

Some things to try

First, NinjaTrader states that it's not compatible with Microsoft OneDrive.  I believe it's because One Drive by default tries to back up your My Documents folder continually, and NT stores a lot of settings within that folder tree.  It's possible that if OneDrive and NT try to open the same failed at once, it could cause problems with NT.  When you run NT, you modify files in the NinjaTrader 8 folder within My Documents, which OneDrive then tries to back up as they're newly modified. By disabling that automatic backup, you prevent OneDrive and NT from competing with each other to access files.  That's done via the OneDrive settings, usually reachable via the tool tray icon (at the right side of the taskbar).  You can try just temporarily shutting it off and see if NT starts.

Starting NT in administrator (higher privilege) mode might help.  Click the start button, then type ninjatrader to see the NT icon in the list, and RIGHT-click on it to select run as administrator.  If that works, then your NT needs elevated permissions to work properly.  Y

You can modify that startup shortcut to always start with administrator mode.  Right-click on the start menu icon and choose the Open file location to find the startup shortcut, and modify it to always use administrator mode.  The images below show the setting for modifying the startup shortcut to start NT in administrator mode each time.

Another thing that may help in identifying what might be causing NT to crash at startup is to start NT in safe mode to see if it starts with only NinjaTrader's installation active (that is, all 3rd party addons are ignored).  If you search the start menu for ninjatrader, you may see an icon to start NT in safe mode, as shown in the above image.  If not, holding down the control key when you click on the NinjaTrader startup icon brings up NT in safe mode.  You can confirm it's in safe mode by checking the Help/About menu in NT's Control Center. If it doesn't have the error when starting in safe mode, then something that was added is likely creating the problem.  In that case, reinstalling NT with no addons, and then one-by-one installing addons and testing if it starts without error will identify the culprit.  To reinstall NT, you can rename your My Documents version of the NinjaTrader 8 folder so a new clean version gets installed, and you can reach your old configuration if you need to in the future.

Here's a screenshot showing the safe mode startup option when searching the start menu for ninjatrader

Here's the Help/About popup that shows Safe Mode under the Version heading when running in safe mode (when just the NinjaTrader-installed parts of the application are loaded).

Again, if this doesn't resolve the issue, then contacting NinjaTrader support may offer additional things to try.