--- a/devtools/server/tests/mochitest/test_webextension-addon-debugging-reload.html
+++ b/devtools/server/tests/mochitest/test_webextension-addon-debugging-reload.html
@@ -101,16 +101,19 @@ async function test_reload_addon() {
   // is finally uninstalled.
 
   let {client} = addonTarget;
   let waitDebuggingClientClosed = new Promise(resolve => {
     addonTarget.once("close", resolve);
   });
 
   let waitShutdown = promiseWebExtensionShutdown();
+  // Disabling the add-on before uninstalling is necessary to cause tests to
+  // pass. This might be indicative of a bug in XPIProvider. Bug 992396.
+  addon.userDisabled = true;
   addon.uninstall();
   await waitShutdown;
 
   info("Waiting the addon target to be closed on addon uninstall");
   await waitDebuggingClientClosed;
 
   // Debugging client has to be closed explicitly when
   // the target has been created as remote.