diff --git a/hsdev.cabal b/hsdev.cabal
--- a/hsdev.cabal
+++ b/hsdev.cabal
@@ -1,5 +1,5 @@
 name:                hsdev
-version:             0.3.2.0
+version:             0.3.2.1
 synopsis:            Haskell development library
 description:
   Haskell development library and tool with support of autocompletion, symbol info, go to declaration, find references, hayoo search etc.
diff --git a/src/HsDev/Database/Update.hs b/src/HsDev/Database/Update.hs
--- a/src/HsDev/Database/Update.hs
+++ b/src/HsDev/Database/Update.hs
@@ -344,10 +344,12 @@
 			mlocs <- liftM
 				(filter (`S.member` packageDbMods)) $
 				(inSessionGhc $ listModules opts pdbs packages')
-			Log.sendLog Log.Trace $ "{} modules found" ~~ length mlocs
 			let
+				umlocs = uniqueModuleLocations mlocs
+			Log.sendLog Log.Trace $ "{} modules found, {} unique" ~~ length mlocs ~~ length umlocs
+			let
 				packageDbMods' = SQLite.query "select m.id, m.file, m.cabal, m.install_dirs, m.package_name, m.package_version, m.installed_name, m.exposed, m.other_location, m.inspection_time, m.inspection_opts from modules as m, package_dbs as ps where m.package_name == ps.package_name and m.package_version == ps.package_version and ps.package_db == ?;" (SQLite.Only (topPackageDb pdbs))
-			scan packageDbMods' ((,,) <$> mlocs <*> pure [] <*> pure Nothing) opts $ \mlocs' -> do
+			scan packageDbMods' ((,,) <$> umlocs <*> pure [] <*> pure Nothing) opts $ \mlocs' -> do
 				ms <- inSessionGhc $ browseModules opts pdbs (mlocs' ^.. each . _1)
 				Log.sendLog Log.Trace $ "scanned {} modules" ~~ length ms
 				sendUpdateAction $ timer "updated package-db modules" $ do
@@ -375,10 +377,12 @@
 			mlocs <- liftM
 				(filter (`S.member` packageDbMods)) $
 				(inSessionGhc $ listModules opts pdbs packages')
-			Log.sendLog Log.Trace $ "{} modules found" ~~ length mlocs
 			let
+				umlocs = uniqueModuleLocations mlocs
+			Log.sendLog Log.Trace $ "{} modules found, {} unique" ~~ length mlocs ~~ length umlocs
+			let
 				packageDbStackMods = liftM concat $ forM (packageDbs pdbs) $ \pdb -> SQLite.query "select m.id, m.file, m.cabal, m.install_dirs, m.package_name, m.package_version, m.installed_name, m.exposed, m.other_location, m.inspection_time, m.inspection_opts from modules as m, package_dbs as ps where m.package_name == ps.package_name and m.package_version == ps.package_version and ps.package_db == ?;" (SQLite.Only pdb)
-			scan packageDbStackMods ((,,) <$> mlocs <*> pure [] <*> pure Nothing) opts $ \mlocs' -> do
+			scan packageDbStackMods ((,,) <$> umlocs <*> pure [] <*> pure Nothing) opts $ \mlocs' -> do
 				ms <- inSessionGhc $ browseModules opts pdbs (mlocs' ^.. each . _1)
 				Log.sendLog Log.Trace $ "scanned {} modules" ~~ length ms
 				sendUpdateAction $ timer "updated package-db-stack modules" $ do
diff --git a/src/HsDev/Scan/Browse.hs b/src/HsDev/Scan/Browse.hs
--- a/src/HsDev/Scan/Browse.hs
+++ b/src/HsDev/Scan/Browse.hs
@@ -5,6 +5,7 @@
 	listModules,
 	browseModules, browseModules',
 	-- * Helpers
+	uniqueModuleLocations,
 	readPackage, readPackageConfig, ghcModuleLocation,
 	packageConfigs, packageDbModules, lookupModule_,
 	modulesPackages, modulesPackagesGroups, withEachPackage,
@@ -32,8 +33,8 @@
 import HsDev.Error
 import HsDev.Tools.Ghc.Worker (GhcM, tmpSession, formatType)
 import HsDev.Tools.Ghc.Compat as Compat
-import HsDev.Util (ordNub)
-import System.Directory.Paths (canonicalize)
+import HsDev.Util (ordNub, uniqueBy)
+import System.Directory.Paths (fromFilePath, normalize)
 
 import qualified ConLike as GHC
 import qualified DataCon as GHC
@@ -72,7 +73,7 @@
 listModules opts dbs pkgs = do
 	tmpSession dbs (opts ++ packagesOpts)
 	ms <- packageDbModules
-	sequence [ghcModuleLocation p m e | (p, m, e) <- ms]
+	return $ ordNub [ghcModuleLocation p m e | (p, m, e) <- ms]
 	where
 		packagesOpts = ["-package " ++ show p | p <- pkgs]
 
@@ -82,24 +83,20 @@
 browseModules :: [String] -> PackageDbStack -> [ModuleLocation] -> GhcM [InspectedModule]
 browseModules opts dbs mlocs = do
 	tmpSession dbs opts
-	liftM concat . withEachPackage (const $ browseModules' opts) $ mlocs
+	liftM concat . withEachPackage (const $ browseModules' opts) $ ordNub mlocs
 
 -- | Inspect installed modules, doesn't set session and package flags!
 browseModules' :: [String] -> [ModuleLocation] -> GhcM [InspectedModule]
 browseModules' opts mlocs = do
 	ms <- packageDbModules
-	mlocsDb <- sequence [ghcModuleLocation p m e | (p, m, e) <- ms]
 	midTbl <- newLookupTable
 	sidTbl <- newLookupTable
 	let
-		lookupModuleId p' m' e' = do
-			mloc' <- ghcModuleLocation p' m' e'
-			modId' <- ghcModuleId p' m' e'
-			lookupTable mloc' modId' midTbl
-	liftM catMaybes $ sequence [browseModule' mloc lookupModuleId (cacheInTableM sidTbl) p m e | ((p, m, e), mloc) <- zip ms mlocsDb, mloc `S.member` mlocs']
+		lookupModuleId p' m' e' = lookupTable (ghcModuleLocation p' m' e') (ghcModuleId p' m' e') midTbl
+	liftM catMaybes $ sequence [browseModule' lookupModuleId (cacheInTableM sidTbl) p m e | (p, m, e) <- ms, ghcModuleLocation p m e `S.member` mlocs']
 	where
-		browseModule' :: ModuleLocation -> (GHC.PackageConfig -> GHC.Module -> Bool -> GhcM ModuleId) -> (GHC.Name -> GhcM Symbol -> GhcM Symbol) -> GHC.PackageConfig -> GHC.Module -> Bool -> GhcM (Maybe InspectedModule)
-		browseModule' mloc modId' sym' p m e = tryT $ runInspect mloc $ inspect_ (return $ InspectionAt 0 (map fromString opts)) (browseModule modId' sym' p m e)
+		browseModule' :: (GHC.PackageConfig -> GHC.Module -> Bool -> GhcM ModuleId) -> (GHC.Name -> GhcM Symbol -> GhcM Symbol) -> GHC.PackageConfig -> GHC.Module -> Bool -> GhcM (Maybe InspectedModule)
+		browseModule' modId' sym' p m e = tryT $ runInspect (ghcModuleLocation p m e) $ inspect_ (return $ InspectionAt 0 (map fromString opts)) (browseModule modId' sym' p m e)
 		mlocs' = S.fromList mlocs
 
 browseModule :: (GHC.PackageConfig -> GHC.Module -> Bool -> GhcM ModuleId) -> (GHC.Name -> GhcM Symbol -> GhcM Symbol) -> GHC.PackageConfig -> GHC.Module -> Bool -> GhcM Module
@@ -170,6 +167,12 @@
 tryT :: MonadCatch m => m a -> m (Maybe a)
 tryT act = catch (fmap Just act) (const (return Nothing) . (id :: SomeException -> SomeException))
 
+-- | There can be same modules (same package name, version and module name) installed in different locations
+-- Select first one of such modules
+uniqueModuleLocations :: [ModuleLocation] -> [ModuleLocation]
+uniqueModuleLocations = uniqueBy nameId' where
+	nameId' mloc = (,) <$> (preview modulePackage mloc) <*> (preview installedModuleName mloc)
+
 readPackage :: GHC.PackageConfig -> ModulePackage
 readPackage pc = ModulePackage (fromString $ GHC.packageNameString pc) (fromString $ showVersion (GHC.packageVersion pc))
 
@@ -179,11 +182,11 @@
 	(map (fromString . GHC.moduleNameString . Compat.exposedModuleName) $ GHC.exposedModules pc)
 	(GHC.exposed pc)
 
-ghcModuleLocation :: MonadIO m => GHC.PackageConfig -> GHC.Module -> Bool -> m ModuleLocation
-ghcModuleLocation p m = liftIO . canonicalize . InstalledModule (map fromString $ GHC.libraryDirs p) (readPackage p) (fromString $ GHC.moduleNameString $ GHC.moduleName m)
+ghcModuleLocation :: GHC.PackageConfig -> GHC.Module -> Bool -> ModuleLocation
+ghcModuleLocation p m = InstalledModule (map (normalize . fromFilePath) $ GHC.libraryDirs p) (readPackage p) (fromString $ GHC.moduleNameString $ GHC.moduleName m)
 
-ghcModuleId :: MonadIO m => GHC.PackageConfig -> GHC.Module -> Bool -> m ModuleId
-ghcModuleId p m e = ModuleId (fromString mname') <$> (ghcModuleLocation p m e) where
+ghcModuleId :: GHC.PackageConfig -> GHC.Module -> Bool -> ModuleId
+ghcModuleId p m e = ModuleId (fromString mname') (ghcModuleLocation p m e) where
 	mname' = GHC.moduleNameString $ GHC.moduleName m
 
 packageConfigs :: GhcM [GHC.PackageConfig]
diff --git a/src/HsDev/Symbols/Location.hs b/src/HsDev/Symbols/Location.hs
--- a/src/HsDev/Symbols/Location.hs
+++ b/src/HsDev/Symbols/Location.hs
@@ -119,12 +119,12 @@
 instance Ord ModuleLocation where
 	compare l r = compare (locType l, locNames l) (locType r, locNames r) where
 		locType :: ModuleLocation -> Int
-		locType (FileModule _ _) = 0
-		locType (InstalledModule _ _ _ _) = 1
-		locType (OtherLocation _) = 2
+		locType FileModule{} = 0
+		locType InstalledModule{} = 1
+		locType OtherLocation{} = 2
 		locType NoLocation = 3
 		locNames (FileModule f _) = [f]
-		locNames (InstalledModule dirs _ nm _) = nm : dirs
+		locNames (InstalledModule dirs _ nm _) = nm : dirs  -- dirs already includes name of package
 		locNames (OtherLocation n) = [n]
 		locNames NoLocation = []
 
diff --git a/src/System/Directory/Paths.hs b/src/System/Directory/Paths.hs
--- a/src/System/Directory/Paths.hs
+++ b/src/System/Directory/Paths.hs
@@ -8,7 +8,8 @@
 	Paths(..),
 	canonicalize,
 	absolutise,
-	relativise
+	relativise,
+	normalize
 	) where
 
 import Control.Lens
@@ -83,3 +84,11 @@
 -- | Relativise paths
 relativise :: Paths a => Path -> a -> a
 relativise parent = over paths (makeRelative (parent ^. path))
+
+-- | Normalize paths, with workaround for Windows drives
+normalize :: Paths a => a -> a
+normalize = over paths normalizePath' where
+	normalizePath' :: FilePath -> FilePath
+	normalizePath' = fixDrive . normalise
+	fixDrive :: FilePath -> FilePath
+	fixDrive = uncurry joinDrive . over _1 (addTrailingPathSeparator . dropWhileEnd isPathSeparator) . splitDrive