When you come across the replication of folder in a computer, if you clicked on file explorer or open any file from a right-clicked Start menu, is an issue with the folder windows. This is not a peculiar trouble and can be caused by different factors like malicious software attacks and the enabling of the 'launch folder windows in a separate process' at the advanced settings of the File Explorer Options. You are required to scan your system with Anti-virus or malware removal tools in the case of any attacks. To do that you can visit this LINK.
Image of a duplicated folder
In clean Windows 10 operating system the major cause is the enabled 'launch folder windows in a separate process' at the File Explorer Options. It leads to sudden glitch of the screen before opening the folder in two separate windows - thereby using more of your system memory and crowding your task manager.
To fix this issue you need to follow the instruction below. It is an easy and quick means to find a solution to the problem.
Note: The File Explorer Options feature may be moved to 'System' section of Settings or somewhere else in the future(Windows 10 is still going through development stages).
Image showing Windows Key + R in red
STEP 1: Press Windows Key + R to open 'Run' dialog.
Image showing red arrow pointing to control appwiz.cpl in Run dialog
STEP 2: Type or copy and paste control appwiz.cpl into 'Run' and click 'OK' to continue.
Red arrow pointing to Control Panel Home link
STEP 3: Click on 'Control Panel Home' link to the top left-hand corner of your screen.
Image of red arrow indicating Appearance and Personalization
STEP 4: Click on 'Appearance and Personalization' to continue.
Red arrow pointing to File Explore Options
STEP 5: Click on 'File Explorer Options' feature at the 'Control Panel' to open it.
Red arrows pointing to process
STEP 6: Next, click on 'View' tab and look for 'Launch folder windows in a separate process' under 'Advanced Settings'.
Three red arrows indicating process
STEP 7: Clear the little box beside 'Launch folder windows in a separate process' , click on 'Apply' and click on 'OK' to close the dialog.