If you host your own data and your jmc server is part of a domain, we need to have read/write access to all of the jmc folders that exist on that server.
Step One: On your Windows server, launch IIS Manager by going to the Start menu > Administrative Tools > Internet Information Services (IIS) Manager.
Step Two: Click the "+" in front of your server name in the upper left corner. Then click "Application Pools" underneath it.
Step Three: Right-click on the jmc application pool in the middle and select "Advanced Settings".
Step Four: In the "Process Model" section, click "Identity", and then click the "..." button to the right of ApplicationPoolIdentity.
Step Five: In the "Built-in Account" field, change it to "LocalSystem" and click "OK" twice.
Step Six: While the jmc application pool is still highlighted, click "Stop" to the far right and, after it stops, click "Start" to restart the application pool with your changes.
Step Seven: Now do the same procedure on the remaining folders.