In Windows and Mac systems, some files and folders containing data critical to the performance of the operating system are hidden. Hidden folders can be viewed at any time, using the Control Panel on Windows PCs, and the Terminal on Mac systems.
Steps
Method 1 of 3: Windows 8 / Windows 7 / Windows Vista

Step 1. Click “Start” and select “Control Panel”
The control panel window will open and display on the screen.
If you are using Windows 8, go to the "Start" screen, start typing "Control Panel", and select this option when it appears in the search menu

Step 2. Click “Appearance and Personalization”, then click “Folder Options”
The folder options dialog box will then open.

Step 3. Click on the "View" tab, then scroll down to the list of advanced settings to find "Hidden files and folders"

Step 4. Click “Show hidden files, folders and drives”, then click OK
On Windows Vista, this option is called "Show hidden files and folders".

Step 5. Click "Apply" and then close the folder options dialog box
All hidden folders should now be displayed.
Method 2 of 3: Windows XP

Step 1. Click “Start” and select “My Computer”

Step 2. Click “Tools” at the top of the “My Computer” window and select “Folder Options”
The "Folder Options" dialog box will appear on the screen.

Step 3. Click the "View" tab, then scroll down to the "Advanced Settings" list to find "Hidden Files and Folders"

Step 4. Click “Show hidden files and folders”, then click OK

Step 5. Click “Apply”, then close the “Folder Options” dialog box
All hidden folders will now be displayed.
Method 3 of 3: Mac

Step 1. Open the “Applications” folder and click “Utilities”

Step 2. Click on "Terminal"
The Terminal application will launch.

Step 3. In Terminal, enter the following command, then press "Enter":
defaults write com.apple.finder AppleShowAllFiles YES. This command allows you to change Mac preferences to show hidden files and folders.

Step 4. In Terminal, enter the following command, then press "Enter":
killall Finder. This command closes and relaunches all open "Finder" windows. All hidden folders will now be displayed.