I am using Windows 7 HOME on a Dell PC. I have indexed everything. When I do a search of a directory by datemodified, certain files do not appear, although others in that same directory modified on the same day *do*. Very puzzling.

If I click on one of those files and look at properties --> details, down near the bottom it has a DATE modified that is completely wrong, often months or years out of date. If I find the file with a different search (like by name) the "date modified" column shows that older date, rather than the correct one.

Since I backup my files daily, using a datemodified search to find the ones that have changed, the inability to be sure I'm finding them all is a problem.

The missing files are always .doc or .xls files, rather than the newer versions, but it *does* find some doc or xls files, even in the same folder, and I'd PREFER not to update everything to the newer version as not everyone can read them.

Anybody else having this problem?From what you describe it would appear that the Windows 7 search feature does not keep an up-to-date index on and why do you use this method instead of some other method have been recently changed.
It would be helpful if you could describe what type of backup system you are using. On the Microsoft website they recommend using a backup program that is part of Windows 7, but no mention is made of backing up files modified on a certain date.
The Windows 7 backup feature backs up files on a schedule. Apparently you are not using that method.
Please describe in a little bit more detail about how you do your backups. Have you used this method before on an earlier Windows operating system? And did it did work as expected?
Sorry I don't have the definite answer for your problem. Many users choose various backup methods. One is to make an image file of an entire partition that contains files of interest. And other method is to synchronize two directories, one on a local machine and one on a network server. Additionally, there are third-party programs that may do a better job than the tools available in Windows 7.

I believe you are correct that there is something buggy about how Windows 7 keeps its index.  On my previous computer (through April 2010!) late each day I would just do a search of my main directory (a large one, with many subdirectories) and tell Windows XP to find all the files and folders that had been modified today. As far as I can tell, it never missed any of them. On a weekly basis, I would tell it to find all the files modified in the previous week. It never missed any of them doing it that way either. This is (or was) a nice simple way to do a daily or weekly backup of my files. Periodically, I still backup the entire main directory onto a CD or DVD, but I still like my daily or weekly flash backups!

If I need to learn about a different method intrinsic to Windows 7, that's not unreasonable, but it isn't the purpose of my post. My post was asking about the search in Windows 7. There are many reasons to want to find *all* the files with a certain characteristic, not just backing them up. If the search doesn't work properly, it's a major bug. I was HOPING there was something I needed to tweak to make it work right!

The only thing they admit to, so far, is that it can not correctly keep Media files up to date. But that is a rather serious problem. Many users want to use Windows 7 to catalog their songs and videos.

Sorry I don't have a clue as to how to fix this.
For what it is wroth here are a few SITES I have looked at, but I  did not find a clear answer to the problem.

This one says he re boots in Vista to do a search.
http://www.osattack.com/windows-7/windows-7-search-sucks/

Fix Windows 7 Search By Installing Hotfix
http://www.troublefixers.com/fix-windows-7-start-menu-search-problem/

This one got my interest. The response was from a MS support man.
http://social.answers.microsoft.com/Forums/en-US/w7files/thread/80bfb0e1-ce2a-493c-ac60-1e9abec26cfa

Nice tutorial and user comments.
http://www.neowin.net/news/main/09/01/15/windows-7-explorer-search-overviewHonestly, Windows search function always sucked.
Personally, I stopped using it long time ago and I rely on 3rd party program, SuperFinder: http://fsl.sytes.net/ssearchxt.html