In what way does setting the PST to read-only improve the security of the PST file? Is your interest in the protection of the PST file? Or, is your actual intention the protection of the individual email elements in the PSTs?
As X1 accesses a PST we must have read access so that we can determine if we need to update the index with regard to that PST. X1's own action of indexing the PST may cause the PST files modification date to change - but the dates of the email items the PST holds are not affected - and again - isn't the integrity of the email items themselves what we really are trying to preserve?
You might see this same type of date modification issue from other utilities such as a disk defragmenter that relocates or defragments the PST, an Anti-Virus tool that might need to scan the PST for the protection of your system, or even for a scheduled backup of the data on your system.
In the end what we're seeing here is that PST files, while used routinely to hold "old unchanging email data", may not be "static" unchanging files. Our computer systems are "living breathing entities". Stuff happens - intentionally or unintentionally, actively or background passively, that can affect the time stamps of our files; even files whose job is to simply sit there storing history.
As X1 accesses a PST we must have read access so that we can determine if we need to update the index with regard to that PST. X1's own action of indexing the PST may cause the PST files modification date to change - but the dates of the email items the PST holds are not affected - and again - isn't the integrity of the email items themselves what we really are trying to preserve?
You might see this same type of date modification issue from other utilities such as a disk defragmenter that relocates or defragments the PST, an Anti-Virus tool that might need to scan the PST for the protection of your system, or even for a scheduled backup of the data on your system.
In the end what we're seeing here is that PST files, while used routinely to hold "old unchanging email data", may not be "static" unchanging files. Our computer systems are "living breathing entities". Stuff happens - intentionally or unintentionally, actively or background passively, that can affect the time stamps of our files; even files whose job is to simply sit there storing history.