diff --git a/spec/package-manager-spec.coffee b/spec/package-manager-spec.coffee
index 8710927df..aa0b2d26f 100644
--- a/spec/package-manager-spec.coffee
+++ b/spec/package-manager-spec.coffee
@@ -445,11 +445,12 @@ describe "PackageManager", ->
           expect(console.warn).not.toHaveBeenCalled()
 
     it "passes the activate method the package's previously serialized state if it exists", ->
-      pack = atom.packages.loadPackage("package-with-serialization")
+      pack = null
       waitsForPromise ->
-        pack.activate()  # require main module
+        atom.packages.activatePackage("package-with-serialization").then (p) -> pack = p
       runs ->
-        atom.packages.setPackageState("package-with-serialization", {someNumber: 77})
+        expect(pack.mainModule.someNumber).not.toBe 77
+        pack.mainModule.someNumber = 77
         atom.packages.deactivatePackage("package-with-serialization")
         spyOn(pack.mainModule, 'activate').andCallThrough()
       waitsForPromise ->
diff --git a/src/package-manager.coffee b/src/package-manager.coffee
index 3a3a74711..636286640 100644
--- a/src/package-manager.coffee
+++ b/src/package-manager.coffee
@@ -487,6 +487,7 @@ class PackageManager
   # Deactivate the package with the given name
   deactivatePackage: (name) ->
     pack = @getLoadedPackage(name)
+    @serializePackage(pack)
     pack.deactivate()
     delete @activePackages[pack.name]
     delete @activatingPackages[pack.name]