Whenever I want to install PhpED it shows an “error opening file for writing” error in Windows 10. I don’t know why this error shows, and how to fix this issue. Any suggestions will be appreciated.

What file does it fail to open for writing?
Try to run installer with /LOG=C:\Users\MyAccountName\log.txt option (where myaccountname is your account name, so the target directory is 100% writable) and check what preceded the issue.
Check if file can be open for writing -- e.g. correct access permissions are set for parent directory.
You can also try to reboot.

Thanks for replying. I'm sorry for not applying the processes you mentioned. But I am trying to apply your processes. Then let you know.

Hello. Follow the link bellow:

thank for posting https://digicruncher.com/error-opening-file-for-writing/
I think that there are too many variants on this post and some of them are rather unsafe.
If setup is run with /LOG="c:\path\to\log.txt" option, this log will show what exact file caused the problem and at what stage. No need to guess, no need to iterate through all the variants.

BTW In 99% reboot helps -- especially if there is some process in background like PhpED itself remained from, for example, previous installation.