diff --git a/repository/Grease-Pharo100-Core.package/GRPharoPlatform.class/instance/newTemporaryFileNamed..st b/repository/Grease-Pharo100-Core.package/GRPharoPlatform.class/instance/newTemporaryFileNamed..st
index 5e778cdd..29d781b7 100644
--- a/repository/Grease-Pharo100-Core.package/GRPharoPlatform.class/instance/newTemporaryFileNamed..st
+++ b/repository/Grease-Pharo100-Core.package/GRPharoPlatform.class/instance/newTemporaryFileNamed..st
@@ -1,4 +1,7 @@
 files
 newTemporaryFileNamed: aName
 
-	^ (FileLocator temp / aName) pathString
\ No newline at end of file
+	| newFile |
+	newFile := FileLocator temp / aName.
+	newFile exists ifTrue: [ GRError new signal: 'A (temporary) file with name ', aName, ' already exists.' ].
+	^ newFile pathString
\ No newline at end of file
diff --git a/repository/Grease-Pharo100-Core.package/monticello.meta/categories.st b/repository/Grease-Pharo100-Core.package/monticello.meta/categories.st
index ecc9aa78..47e57aa2 100644
--- a/repository/Grease-Pharo100-Core.package/monticello.meta/categories.st
+++ b/repository/Grease-Pharo100-Core.package/monticello.meta/categories.st
@@ -1 +1 @@
-SystemOrganization addCategory: #'Grease-Pharo100-Core'!
+self packageOrganizer ensurePackage: #'Grease-Pharo100-Core' withTags: #()!
diff --git a/repository/Grease-Tests-Core.package/GRPlatformTest.class/instance/testNewTemporaryFileNamed.st b/repository/Grease-Tests-Core.package/GRPlatformTest.class/instance/testNewTemporaryFileNamed.st
index 68d6ff3c..354c5403 100644
--- a/repository/Grease-Tests-Core.package/GRPlatformTest.class/instance/testNewTemporaryFileNamed.st
+++ b/repository/Grease-Tests-Core.package/GRPlatformTest.class/instance/testNewTemporaryFileNamed.st
@@ -1,13 +1,16 @@
 tests-files
 testNewTemporaryFileNamed
 
-	| temporaryFile |
+	| temporaryFile fileName |
+	fileName := 'GRPlatformTestTemporaryFile'.
 	[
-		temporaryFile := GRPlatform current newTemporaryFileNamed: 'test_temporary'.
+		temporaryFile := GRPlatform current newTemporaryFileNamed: fileName.
 		GRPlatform current
 			writeFileStreamOn: temporaryFile
 			do: [ :str | str nextPutAll: 'test temporary' ]
 			binary: false.
-		self assert: (GRPlatform current fileExists: temporaryFile)
+		self assert: (GRPlatform current fileExists: temporaryFile).
+		self should: [ GRPlatform current newTemporaryFileNamed: fileName ] raise: GRError.
 	] ensure: [ GRPlatform current deleteFile: temporaryFile ].
-	self deny: (GRPlatform current fileExists: temporaryFile)
\ No newline at end of file
+	self deny: (GRPlatform current fileExists: temporaryFile).
+	
\ No newline at end of file