I had to do a System Restore to fix a problem with my computer. Bitdefender Free was running fine but I had to uninstall it and Bitdefender Agent using Control Panel/Programs and Features before I could do the System Restore. 
I also downloaded the Uninstall Tool from here, ran it, and deleted any leftover Bitdefender folders in C:\Program Files https://www.bitdefender.com/site/view/uninstall_consumer_trial.html
The System Restore fixed the Windows problem. I downloaded the Bitdefender install file from here: https://www.bitdefender.com/solutions/free.html
When I ran it I get the cannot copy installer error. I have seen others here and on other forums getting the same error message.
    
        
            
    
1.     This time I used Revo Uninstaller to uninstall Bitdefender Agent and its registry entries, Ccleaner’s registry cleaner, and manually deleted any Bitdefender registry entries with regedit.
2.     I ran chkdsk on C:\, dism, and sfc /scannow. No corrupt files found.
    
        
            
    
3.     Ran scans of C:\ drive with Malawarebytes Antimalware, ADWcleaner, and Windows Defender. Nothing found.
4.     Deleted all files from my C:\Users\......\Appdata\Local\Temp directory
5.     Turned off Windows Defender and all Firewalls.
6.     Followed the steps here: https://www.bitdefender.com/consumer/support/answer/9354/?clickid=2q8yMh2gTxyLRLhwUx0Mo3bzUkEzXhWdRytIUE0&irgwc=1&MPid=10078&cid=aff%7Cc%7CIR
7.     Ran the installation file, bitdefender_online.exe, again. Same error message, Cannot copy installer.
8.     Uninstalled Bitdefender totally again. Created a new Bitdefender account, logged in to Bitdefender Central, and        downloaded the bitdefender_windows_............exe installation file.
9.     Turned Windows Defender and firewalls off and tried to install it. I got this error message:
    
        
            
    
When I tried to run the uninstall tool I got this:
    
        
            
    
I’m throwing in the towel for now. Doing a Windows re-install is not an option. Windows and everything else are running fine.
Anyone here or in support have any suggestions???