Android Question android.support.v7.widget.Toolbar Problem

I tried to clean up my file system. Oops. Now having this problem.

Have used AppCompat menu in many projects. Updated the SDK two times.

Clueless.

Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v7.widget.Toolbar" on path: DexPathList[[zip file "/data/app/com.mhm.pearlpal-FZo7esy-c1lWWFbWdL5V-w==/base.apk"],nativeLibraryDirectories=[/data/app/com.mhm.pearlpal-FZo7esy-c1lWWFbWdL5V-w==/lib/arm64, /system/lib64, /system/vendor/lib64]]