Is there a way to prevent a file from being deleted?

Solution 1:

Under NTFS you can alter the access rights for users and groups either at a folder level or at a file level.

Right click on a file or folder and go to the security tab. You can then remove users rights for deleting / modifying a file. Ensure you leave the administrator and administrators full rights. Also, if it on a domain ensure that both the local administrator and domain administrators have full access rights.

Solution 2:

Just remove modify permissions from anyone but the user account that creates the file. This kind of thing is exactly what NTFS rights are for.

Solution 3:

"accumulated information that will take forever to recreate" - the time to prepare a backup / restore procedure is right now. Don't wait until the file is somehow deleted or overwritten, or the disk fails. A proper backup strategy with proven (and tested) restore capability is a must.

Solution 4:

If you want a full logical protection, since Deny takes precedence on Allow, File Properties > Security tab > Advanced Security Setting , Deny to Everybody the delete right on this file.

Again, a full backup of this file is in order.