If you've recently upgraded your operating system to Windows 10 and your Start menu is missing, don't worry, you can still get it back.
Steps
Method 1 of 2: Check and repair corrupted files

Step 1. Check to see if you have options when you right-click on the location where the Start menu used to be
If yes, then click on the "Task Manager" option.
Otherwise, press the key combination (Ctrl + Alt + Delete). After that, several options will appear on the screen, among which there will be "Task Manager"

Step 2. In the "Task Manager" window, click on the "File" menu, and then select "Run a new task"

Step 3. Enter "powershell" and make sure there is a check mark next to the "Create a task with administrator rights" option
This is what you will see

Step 4. Run System File Checker
After the line C: \ WINDOWS \ system32> you must enter (or insert) "sfc / scannow" (without quotes).
Run file scan. Depending on the computer, the check will either be very fast, or you will have to wait

Step 5. Take a look at the test results
Your problem may have been resolved. Read what is written on the screen, or better yet, take a screenshot of the screen.

Step 6. Restart your computer and check if the Start button is back
Method 2 of 2: Reinstall Windows Apps

Step 1. If the first method doesn't work for you, reinstall Windows apps
Although the problem is not with the applications themselves, it can still help solve it.

Step 2. Start Task Manager (as mentioned earlier) and start another task with administrator rights

Step 3. Enter powershell and then write (or paste) the following command
Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$ ($ _. InstallLocation) AppXManifest.xml"}

Step 4. Wait for the process to complete and then restart your computer
The Start menu should be back in place.