Search OST file data with the Outlook search box because Outlook opens the offline file for you. Four methods work. They are Instant Search, Advanced Find, a longer offline range and converter software. Older mail is missing from results when the range spans only a few months. Software opens an orphan OST file that Outlook rejects. Type a few words first and narrow the scope next.
You type a name in the search box and Outlook shows nothing from last year. Your mail exists on the server but the offline file stores only part of it.
This guide explains how to search OST file data for Microsoft 365 and Exchange accounts and what to do when the file has no profile.
What Does Searching an OST File Mean?
Your OST file is the offline copy of your mailbox. Outlook searches this copy when Cached Exchange Mode is on. Four facts explain the results:
- Offline Range. Cached Exchange Mode syncs mail only for a set period and older items remain on the server.
- Default Range. Microsoft lists the defaults by disk size as 1 month up to 32 GB and 3 months from 32 GB to below 64 GB and 12 months from 64 GB.
- Other Folders. The range does not limit Calendar, Contacts, Tasks, Journal, Notes and Outbox.
- No Direct Access. You do not open the file by name. Outlook opens it through your profile.
Outlook search matches full words or the start of a word. Search for "port" finds "port" and "portal" but not "import".
Which Way Fits Your Case?
Match your case with the table:
| Your Case | Best Step | Method |
|---|---|---|
| Find a sender or word in a folder | Search box | Method #1 |
| Filter by many fields | Advanced Find | Method #2 |
| Older mail is missing in results | Offline range | Method #3 |
| Profile is gone or the file is corrupt | Converter software | Method #4 |
4 Ways to Search an OST File
Methods 1 to 3 need Outlook and your account. Method 4 needs only the file:
| Method | Needs Outlook | Searches Older Mail |
|---|---|---|
| Instant Search | Yes | Only synced mail |
| Advanced Find | Yes | Only synced mail |
| Longer Offline Range | Yes | Yes after a resync |
| Converter Software | No | Yes inside the file |
Method #1: Search OST File Mail With Instant Search (Free)
Instant Search handles most cases. Five steps start a search:
- Select Mail in the navigation bar.
- Click the search box above your messages.
- Type a word or a name. Use quotes for an exact phrase.
- Choose a place in the Scope group.
- Add From, Subject, Has Attachments or Unread in the Refine group.
Note: Use capital AND, OR and NOT between words. Select the X in the search box to clear the results.
Method #2: Find Mail in an OST File With Advanced Find (Free)
Advanced Find filters mail by many fields at once. Four steps open it:
- Click the search box.
- Open Search Tools on the Search tab and select Advanced Find.
- Open the Advanced tab and select Field under Define more criteria.
- Choose All Mail Fields then select a field and a condition and type a value.
Note: Microsoft states Advanced Find does not work with auto expanding archives.
Method #3: Extend the Offline Range for Older Mail (Free)
Results show only items that synced to the offline file. Seven steps extend the range:
- Open Outlook and go to File then Account Settings then Account Settings.
- Double click your Exchange account on the E-mail tab.
- Drag the Mail to keep offline slider to All or a longer period.
- Click Next.
- Click OK when Outlook asks for a restart.
- Click Finish.
- Restart Outlook and wait for the sync.
Note: A larger range starts a full resync of the OST file. Later versions name the slider Download email for the past.
Method #4: Open an OST File Without Outlook Using EmailDoctor OST to PST Converter (Trial Version)
Outlook cannot search the file when the profile is gone or the file is corrupt. EmailDoctor OST to PST Converter opens an orphan or corrupt file without Outlook or an Exchange profile. Work on a duplicate of the file.
Open the Copy in the Converter
Three steps start the scan:
- Start the converter and click Add File.
- Open Select File and browse to the OST copy.
- Choose Quick or Advanced scan and click Add.
Preview the Folders and Save the Mail
Two steps finish the export:
- Select a folder in the list and view the mail in the preview pane.
- Click Export and choose PST then set the destination.
Note: Trial mode saves 25 items from every folder. Export one folder first and then use Method #1 on the new PST file.
How to Read Your Result
Check the result before you adjust a setting:
| Result | Meaning | Next Step |
|---|---|---|
| Results show new mail only | Offline range is short | Method #3 |
| Results stop at one date | Older mail is on the server | Method #3 |
| Search shows no items at all | Index or file problem | Method #4 |
| Outlook cannot open the file | Profile is missing | Method #4 |
Frequently Asked Questions
Can You Search an OST File Without Outlook?
Yes. Converter software opens the OST file without Outlook and shows the folders before you save the mail.
Why is Old Mail Missing From Outlook Search Results?
Cached Exchange Mode syncs only the period set in the offline range. Older items remain on the server.
Which Folder Stores the OST File?
Open Account Settings and the Data Files tab to see the path of the file before you search an OST file.
Does the Search Include the Calendar and Contacts?
Yes. Microsoft states the offline range does not limit Calendar, Contacts, Tasks, Journal, Notes and Outbox.
What is the Free Limit of the Converter?
Trial mode saves 25 items from every folder.
Author’s Verdict
Start with Instant Search to search OST file mail for a quick answer. Advanced Find works when you need many conditions. Extend the offline range when older mail is missing from the results.
Choose converter software when the profile is gone or the file is corrupt. Make every change on a duplicate of the OST file only.
- Search OST file data with the Outlook search box.
- Advanced Find filters many fields.
- Short offline ranges hide older mail.
- Converter software opens an orphan or corrupt file without Outlook.
Next Read: Search Emails in MS Outlook
Also Read: Extract Emails From Outlook OST Files | Synchronizing OST File in Outlook
