When you have different people installing add-ons in JIRA, you can, at times, run into problems, but you might be unsure as to which add-on has caused a certain problem. In these cases, you can use the method of elimination; however, you should first disable all the add-ons, and re-enable them one at a time.
Enabling safe mode will impact your users, so make sure you plan accordingly before doing so.
Perform the following steps to enable safe mode:
Navigate to Administration | Add-ons | Manage add-ons.
Click on the Enter safe mode link at the bottom of the page.
Click on Enter safe mode when you are prompted to confirm the operation.
The window looks like the following screenshot: