FM Server 12 - Cannot Enable plugin on Windows Server 2008 without restarting

Issue report by databuzz

Product

FileMaker Server

Version

12.0.4.405

Operating system version

Windows Server 2008 R2

Description of the issue

I cannot"enable" a FileMaker Server plugin that has been installed from a FileMaker Server Schedule that runs a FileMaker Pro script that uses the Install Plug-In File script step to install a plugin. I get an error "Error 474 Plug-in failed to load" when I attempt to enable a plugin in the FileMaker Server Admin Console.

Steps to reproduce the problem

1. create a FileMaker Pro script in your database that is hosted by FileMaker Server that uses the Install Plug-In File script step to install a plugin (I'm using the free BaseElements plugin)
2. create a FileMaker Server Schedule to perform this FileMaker Pro script
3. run this FileMaker Server Schedule
4. the plugin should appear in the list of available plugins under the Configuration>Database Server> Server Plug-Ins tab
5. click the Enabled tick box to the left of the plug-in name and click the Save button

Expected result

The tick should remain in the Enabled checkbox and no errors should be generated

Actual result

The tick doesn't remain in the Enabled checkbox - it is deselected almost immediately. An error is generated in the log file like this:

Error 474 Plug-in failed to load: BaseElements.fmx

Exact text of any error message(s) that appear

Error 474 Plug-in failed to load: BaseElements.fmx

Configuration information

Only tested on Windows Server 2008 R2

Workaround

Restarting the FileMaker Database Server appears to resolve this.