diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index e9f15b6fa84ca..0fa06d9d2670f 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -332,9 +332,9 @@ namespace ts {
     /*@internal*/
     export interface RecursiveDirectoryWatcherHost {
         watchDirectory: HostWatchDirectory;
+        useCaseSensitiveFileNames: boolean;
         getAccessibleSortedChildDirectories(path: string): ReadonlyArray<string>;
         directoryExists(dir: string): boolean;
-        filePathComparer: Comparer<string>;
         realpath(s: string): string;
     }
 
@@ -345,60 +345,94 @@ namespace ts {
      */
     /*@internal*/
     export function createRecursiveDirectoryWatcher(host: RecursiveDirectoryWatcherHost): (directoryName: string, callback: DirectoryWatcherCallback) => FileWatcher {
-        type ChildWatches = ReadonlyArray<DirectoryWatcher>;
-        interface DirectoryWatcher extends FileWatcher {
-            childWatches: ChildWatches;
+        interface ChildDirectoryWatcher extends FileWatcher {
             dirName: string;
         }
+        type ChildWatches = ReadonlyArray<ChildDirectoryWatcher>;
+        interface HostDirectoryWatcher {
+            watcher: FileWatcher;
+            childWatches: ChildWatches;
+            refCount: number;
+        }
+
+        const cache = createMap<HostDirectoryWatcher>();
+        const callbackCache = createMultiMap<DirectoryWatcherCallback>();
+        const filePathComparer = getStringComparer(!host.useCaseSensitiveFileNames);
+        const toCanonicalFilePath = createGetCanonicalFileName(host.useCaseSensitiveFileNames);
 
         return createDirectoryWatcher;
 
         /**
          * Create the directory watcher for the dirPath.
          */
-        function createDirectoryWatcher(dirName: string, callback: DirectoryWatcherCallback): DirectoryWatcher {
-            const watcher = host.watchDirectory(dirName, fileName => {
-                // Call the actual callback
-                callback(fileName);
+        function createDirectoryWatcher(dirName: string, callback?: DirectoryWatcherCallback): ChildDirectoryWatcher {
+            const dirPath = toCanonicalFilePath(dirName) as Path;
+            let directoryWatcher = cache.get(dirPath);
+            if (directoryWatcher) {
+                directoryWatcher.refCount++;
+            }
+            else {
+                directoryWatcher = {
+                    watcher: host.watchDirectory(dirName, fileName => {
+                        // Call the actual callback
+                        callbackCache.forEach((callbacks, rootDirName) => {
+                            if (rootDirName === dirPath || (startsWith(dirPath, rootDirName) && dirPath[rootDirName.length] === directorySeparator)) {
+                                callbacks.forEach(callback => callback(fileName));
+                            }
+                        });
 
-                // Iterate through existing children and update the watches if needed
-                updateChildWatches(result, callback);
-            });
+                        // Iterate through existing children and update the watches if needed
+                        updateChildWatches(dirName, dirPath);
+                    }),
+                    refCount: 1,
+                    childWatches: emptyArray
+                };
+                cache.set(dirPath, directoryWatcher);
+                updateChildWatches(dirName, dirPath);
+            }
 
-            let result: DirectoryWatcher = {
-                close: () => {
-                    watcher.close();
-                    result.childWatches.forEach(closeFileWatcher);
-                    result = undefined!;
-                },
+            if (callback) {
+                callbackCache.add(dirPath, callback);
+            }
+
+            return {
                 dirName,
-                childWatches: emptyArray
+                close: () => {
+                    const directoryWatcher = Debug.assertDefined(cache.get(dirPath));
+                    if (callback) callbackCache.remove(dirPath, callback);
+                    directoryWatcher.refCount--;
+
+                    if (directoryWatcher.refCount) return;
+
+                    cache.delete(dirPath);
+                    closeFileWatcherOf(directoryWatcher);
+                    directoryWatcher.childWatches.forEach(closeFileWatcher);
+                }
             };
-            updateChildWatches(result, callback);
-            return result;
         }
 
-        function updateChildWatches(watcher: DirectoryWatcher, callback: DirectoryWatcherCallback) {
+        function updateChildWatches(dirName: string, dirPath: Path) {
             // Iterate through existing children and update the watches if needed
-            if (watcher) {
-                watcher.childWatches = watchChildDirectories(watcher.dirName, watcher.childWatches, callback);
+            const parentWatcher = cache.get(dirPath);
+            if (parentWatcher) {
+                parentWatcher.childWatches = watchChildDirectories(dirName, parentWatcher.childWatches);
             }
         }
 
         /**
          * Watch the directories in the parentDir
          */
-        function watchChildDirectories(parentDir: string, existingChildWatches: ChildWatches, callback: DirectoryWatcherCallback): ChildWatches {
-            let newChildWatches: DirectoryWatcher[] | undefined;
-            enumerateInsertsAndDeletes<string, DirectoryWatcher>(
+        function watchChildDirectories(parentDir: string, existingChildWatches: ChildWatches): ChildWatches {
+            let newChildWatches: ChildDirectoryWatcher[] | undefined;
+            enumerateInsertsAndDeletes<string, ChildDirectoryWatcher>(
                 host.directoryExists(parentDir) ? mapDefined(host.getAccessibleSortedChildDirectories(parentDir), child => {
                     const childFullName = getNormalizedAbsolutePath(child, parentDir);
                     // Filter our the symbolic link directories since those arent included in recursive watch
                     // which is same behaviour when recursive: true is passed to fs.watch
-                    return host.filePathComparer(childFullName, host.realpath(childFullName)) === Comparison.EqualTo ? childFullName : undefined;
+                    return filePathComparer(childFullName, normalizePath(host.realpath(childFullName))) === Comparison.EqualTo ? childFullName : undefined;
                 }) : emptyArray,
                 existingChildWatches,
-                (child, childWatcher) => host.filePathComparer(child, childWatcher.dirName),
+                (child, childWatcher) => filePathComparer(child, childWatcher.dirName),
                 createAndAddChildDirectoryWatcher,
                 closeFileWatcher,
                 addChildDirectoryWatcher
@@ -410,14 +444,14 @@ namespace ts {
              * Create new childDirectoryWatcher and add it to the new ChildDirectoryWatcher list
              */
             function createAndAddChildDirectoryWatcher(childName: string) {
-                const result = createDirectoryWatcher(childName, callback);
+                const result = createDirectoryWatcher(childName);
                 addChildDirectoryWatcher(result);
             }
 
             /**
              * Add child directory watcher to the new ChildDirectoryWatcher list
              */
-            function addChildDirectoryWatcher(childWatcher: DirectoryWatcher) {
+            function addChildDirectoryWatcher(childWatcher: ChildDirectoryWatcher) {
                 (newChildWatches || (newChildWatches = [])).push(childWatcher);
             }
         }
@@ -710,7 +744,7 @@ namespace ts {
                         createWatchDirectoryUsing(dynamicPollingWatchFile || createDynamicPriorityPollingWatchFile({ getModifiedTime, setTimeout })) :
                         watchDirectoryUsingFsWatch;
                 const watchDirectoryRecursively = createRecursiveDirectoryWatcher({
-                    filePathComparer: getStringComparer(!useCaseSensitiveFileNames),
+                    useCaseSensitiveFileNames,
                     directoryExists,
                     getAccessibleSortedChildDirectories: path => getAccessibleFileSystemEntries(path).directories,
                     watchDirectory,
diff --git a/src/compiler/watchUtilities.ts b/src/compiler/watchUtilities.ts
index 45ae2e3547828..502e66dac1a60 100644
--- a/src/compiler/watchUtilities.ts
+++ b/src/compiler/watchUtilities.ts
@@ -398,7 +398,7 @@ namespace ts {
             case WatchLogLevel.TriggerOnly:
                 return createFileWatcherWithTriggerLogging;
             case WatchLogLevel.Verbose:
-                return createFileWatcherWithLogging;
+                return addWatch === <any>watchDirectory ? createDirectoryWatcherWithLogging : createFileWatcherWithLogging;
         }
     }
 
@@ -413,6 +413,25 @@ namespace ts {
         };
     }
 
+    function createDirectoryWatcherWithLogging<H, T, U, V, X, Y>(host: H, file: string, cb: WatchCallback<U, V>, flags: T, passThrough: V | undefined, detailInfo1: X | undefined, detailInfo2: Y | undefined, addWatch: AddWatch<H, T, U, undefined>, log: (s: string) => void, watchCaption: string, getDetailWatchInfo: GetDetailWatchInfo<X, Y> | undefined): FileWatcher {
+        const watchInfo = `${watchCaption}:: Added:: ${getWatchInfo(file, flags, detailInfo1, detailInfo2, getDetailWatchInfo)}`;
+        log(watchInfo);
+        const start = timestamp();
+        const watcher = createFileWatcherWithTriggerLogging(host, file, cb, flags, passThrough, detailInfo1, detailInfo2, addWatch, log, watchCaption, getDetailWatchInfo);
+        const elapsed = timestamp() - start;
+        log(`Elapsed:: ${elapsed}ms ${watchInfo}`);
+        return {
+            close: () => {
+                const watchInfo = `${watchCaption}:: Close:: ${getWatchInfo(file, flags, detailInfo1, detailInfo2, getDetailWatchInfo)}`;
+                log(watchInfo);
+                const start = timestamp();
+                watcher.close();
+                const elapsed = timestamp() - start;
+                log(`Elapsed:: ${elapsed}ms ${watchInfo}`);
+            }
+        };
+    }
+
     function createFileWatcherWithTriggerLogging<H, T, U, V, X, Y>(host: H, file: string, cb: WatchCallback<U, V>, flags: T, passThrough: V | undefined, detailInfo1: X | undefined, detailInfo2: Y | undefined, addWatch: AddWatch<H, T, U, undefined>, log: (s: string) => void, watchCaption: string, getDetailWatchInfo: GetDetailWatchInfo<X, Y> | undefined): FileWatcher {
         return addWatch(host, file, (fileName, cbOptional) => {
             const triggerredInfo = `${watchCaption}:: Triggered with ${fileName}${cbOptional !== undefined ? cbOptional : ""}:: ${getWatchInfo(file, flags, detailInfo1, detailInfo2, getDetailWatchInfo)}`;
diff --git a/src/harness/virtualFileSystemWithWatch.ts b/src/harness/virtualFileSystemWithWatch.ts
index 8f3fbe1ad2d4c..572c59bb305fd 100644
--- a/src/harness/virtualFileSystemWithWatch.ts
+++ b/src/harness/virtualFileSystemWithWatch.ts
@@ -352,9 +352,9 @@ interface Array<T> {}`
             if (tscWatchDirectory === Tsc_WatchDirectory.WatchFile) {
                 const watchDirectory: HostWatchDirectory = (directory, cb) => this.watchFile(directory, () => cb(directory), PollingInterval.Medium);
                 this.customRecursiveWatchDirectory = createRecursiveDirectoryWatcher({
+                    useCaseSensitiveFileNames: this.useCaseSensitiveFileNames,
                     directoryExists: path => this.directoryExists(path),
                     getAccessibleSortedChildDirectories: path => this.getDirectories(path),
-                    filePathComparer: this.useCaseSensitiveFileNames ? compareStringsCaseSensitive : compareStringsCaseInsensitive,
                     watchDirectory,
                     realpath: s => this.realpath(s)
                 });
@@ -362,9 +362,9 @@ interface Array<T> {}`
             else if (tscWatchDirectory === Tsc_WatchDirectory.NonRecursiveWatchDirectory) {
                 const watchDirectory: HostWatchDirectory = (directory, cb) => this.watchDirectory(directory, fileName => cb(fileName), /*recursive*/ false);
                 this.customRecursiveWatchDirectory = createRecursiveDirectoryWatcher({
+                    useCaseSensitiveFileNames: this.useCaseSensitiveFileNames,
                     directoryExists: path => this.directoryExists(path),
                     getAccessibleSortedChildDirectories: path => this.getDirectories(path),
-                    filePathComparer: this.useCaseSensitiveFileNames ? compareStringsCaseSensitive : compareStringsCaseInsensitive,
                     watchDirectory,
                     realpath: s => this.realpath(s)
                 });
@@ -373,9 +373,9 @@ interface Array<T> {}`
                 const watchFile = createDynamicPriorityPollingWatchFile(this);
                 const watchDirectory: HostWatchDirectory = (directory, cb) => watchFile(directory, () => cb(directory), PollingInterval.Medium);
                 this.customRecursiveWatchDirectory = createRecursiveDirectoryWatcher({
+                    useCaseSensitiveFileNames: this.useCaseSensitiveFileNames,
                     directoryExists: path => this.directoryExists(path),
                     getAccessibleSortedChildDirectories: path => this.getDirectories(path),
-                    filePathComparer: this.useCaseSensitiveFileNames ? compareStringsCaseSensitive : compareStringsCaseInsensitive,
                     watchDirectory,
                     realpath: s => this.realpath(s)
                 });
diff --git a/src/testRunner/unittests/tsserverProjectSystem.ts b/src/testRunner/unittests/tsserverProjectSystem.ts
index 7e09bae555bab..d2a398849c967 100644
--- a/src/testRunner/unittests/tsserverProjectSystem.ts
+++ b/src/testRunner/unittests/tsserverProjectSystem.ts
@@ -8589,10 +8589,10 @@ export const x = 10;`
                 tscWatchDirectory === Tsc_WatchDirectory.WatchFile ?
                     expectedWatchedFiles :
                     createMap();
-            // For failed resolution lookup and tsconfig files
-            mapOfDirectories.set(projectFolder, 2);
+            // For failed resolution lookup and tsconfig files => cached so only watched only once
+            mapOfDirectories.set(projectFolder, 1);
             // Through above recursive watches
-            mapOfDirectories.set(projectSrcFolder, 2);
+            mapOfDirectories.set(projectSrcFolder, 1);
             // node_modules/@types folder
             mapOfDirectories.set(`${projectFolder}/${nodeModulesAtTypes}`, 1);
             const expectedCompletions = ["file1"];
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index c9267db9a4b7f..840ebc1f259cc 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -1933,9 +1933,6 @@ declare namespace ts {
         getAmbientModules(): Symbol[];
         tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined;
         getApparentType(type: Type): Type;
-        getSuggestionForNonexistentProperty(name: Identifier | string, containingType: Type): string | undefined;
-        getSuggestionForNonexistentSymbol(location: Node, name: string, meaning: SymbolFlags): string | undefined;
-        getSuggestionForNonexistentExport(node: Identifier, target: Symbol): string | undefined;
         getBaseConstraintOfType(type: Type): Type | undefined;
         getDefaultFromTypeParameter(type: Type): Type | undefined;
         /**