How to solve the problem of backup folder access rejection in WinXP

Before re-installing Windows XP, to avoid the loss of important data files, I backed up the files in my documents to drive D, formatted drive C, and re-installed Windows XP, after the installation is complete, the original user account cannot access the backup file of the d disk. Why is access denied?
Cause Analysis: My computer uses the NTFS file system, so all files or folders are restricted by ACL (access control permission. Although the "RTJ" account is used to access files in Windows before and after the system is reinstalled, note that each access account corresponds to a unique SID (Security Identifier ), the ACL function uses SID to determine whether the account can access a file.
After the system is reinstalled, I also use the "RTJ" account to access it, but the SID of the "RTJ" account is different from the previous one. Therefore, after the system is reinstalled, the "RTJ" account cannot access the backup folder.
Solution: To solve this problem, it is actually very simple. In the "Security" tab of the backup folder, re-grant the "RTJ" account access permission.
Step 1: log on to the system with the "Administrator" account, click "Tools> options" in resource manager, and switch to the "View" tab in the "Folder Options" dialog box that appears, cancel "√" before "use simple file sharing" and click "OK, to find the "Security" tab in the Properties dialog box of the backup folder ).
Step 2: Right-click the backup folder on disk D and select "properties". In the displayed Properties dialog box, switch to the "Security" tab, in this case, you will find an "unknown account" project in the "Group or user name" Column (figure 1). This is the "RTJ" account before the system is reinstalled, because the SID value changes after the system is re-installed, the system cannot identify this account, which leads to the "RTJ" account being denied access.
First, delete this unknown account and click "advanced" in the Security tab. The "Advanced Security Settings" dialog box is displayed. Switch to the "owner" tab, the owner of the backup file is an unknown account. Of course, the "RTJ" account cannot be accessed. Change the owner to the "RTJ" Account (figure 2). Remember to select the "Replace sub-container and object owner" option below and click "Apply.
Step 3: In the "Advanced Security Settings" dialog box, switch to the "valid Permissions" tab, click the "add" button, and add the "RTJ" account to the "permission project" list box. During the process of adding an account, be sure to grant "Full Control" to the "RTJ" account, and click "OK" to complete the modification. In this way, the "RTJ" account can access the files in the backup folder without the access being denied.