When search results in a SharePoint document library stop returning the files you expect, or when metadata filters no longer work correctly, the library may need reindexing. This problem happens because SharePoint’s search index becomes outdated after bulk uploads, moved files, or frequent metadata edits. The index is a snapshot of your library’s content and properties, and when it falls behind, search and filtering break. This article explains the correct reindexing process and the best settings to use in Microsoft 365 to restore accurate search results and filtering performance.
Key Takeaways: Reindexing a SharePoint Document Library
- Library Settings > Advanced Settings > Reindex Document Library: The only built-in button to request a full reindex for a single library.
- Site Settings > Search and offline availability > Reindex site: Forces a reindex for all content in the site collection, including all libraries.
- PowerShell cmdlet Request-SPOPageReindex: Triggers reindexing for a specific list or library without waiting for the scheduled crawl.
Why Reindexing Is Needed for SharePoint Document Libraries
SharePoint search relies on a crawl process that reads content, metadata, and permissions from libraries and stores them in a search index. The crawl runs on a schedule set by the SharePoint admin in the Microsoft 365 admin center. By default, continuous crawls run every few minutes for most content, but certain changes can delay updates.
When a document library experiences a large number of simultaneous changes, such as uploading 10,000 files at once, moving folders between libraries, or updating managed metadata columns on hundreds of items, the crawl queue can back up. In these cases, the index may not reflect the current state of the library for hours or even days. Users then see missing files in search results or incorrect values in filter dropdowns.
Reindexing forces SharePoint to schedule a full crawl of that specific library rather than waiting for incremental updates. The process does not rebuild the index from scratch across the entire farm, but it prioritizes the library in the crawl queue. After reindexing, search results and filters should return to normal within a few hours, depending on the size of the library and the current crawl load.
Steps to Reindex a SharePoint Document Library in Microsoft 365
The following steps use the SharePoint browser interface. No admin permissions are required beyond the ability to manage the library settings. If you are a site owner, you can perform these steps yourself.
- Open the Document Library Settings
Navigate to the document library in your browser. Click the gear icon in the upper-right corner, then select Library settings. If you do not see Library settings, you may not have owner permissions for the library. - Go to Advanced Settings
Under the General Settings section, click Advanced settings. This page controls indexing, content approval, and versioning options. - Locate the Reindex Document Library Button
Scroll down to the Search section. You will see a button labeled Reindex Document Library. Click this button. A confirmation dialog appears, warning that reindexing may take time. - Confirm the Reindex Request
Click OK in the confirmation dialog. SharePoint sends a request to the search service to crawl the entire library on the next available crawl cycle. No further action is required. - Monitor Search Results
After 15 to 60 minutes, test search queries in the library or the site. If results still appear incomplete, the crawl may be delayed due to high load. Wait up to 24 hours before repeating the process.
Alternative Method: Reindex the Entire Site
If multiple libraries in the same site collection have search problems, reindex the entire site instead. Go to Site settings > Search and offline availability. Under Indexing Site Content, click Reindex site. This triggers a full crawl of all lists and libraries in the site. Use this method sparingly because it increases load on the search service.
Best Settings for Search and Indexing in Microsoft 365
Reindexing alone does not fix all search problems. The following settings ensure that your document library remains searchable and that filters work correctly after reindexing.
Enable Managed Metadata Columns for Search
Managed metadata columns, such as department or project tags, must be mapped to search managed properties. If they are not mapped, reindexing will not make them searchable. To check, go to Site settings > Search schema > Managed properties. Look for a property that matches your column name. If it does not exist, create a new managed property and map it to the crawled property of the column.
Set the Correct Crawl Schedule
SharePoint admins in Microsoft 365 can adjust the crawl schedule in the admin center. Go to SharePoint admin center > Search > Manage search schema > Crawl schedules. Set incremental crawls to run every 15 minutes during business hours. Full crawls should run weekly during low-traffic periods, such as Saturday night. This schedule keeps the index fresh without overwhelming the farm.
Limit the Number of Items in a Library
SharePoint Online supports up to 30 million items per library, but performance degrades long before that limit. For reliable search and filtering, keep libraries under 500,000 items. Use folders, metadata, or document sets to organize content. If a library exceeds 1 million items, reindexing can take more than 24 hours. Consider splitting content into multiple libraries or using a hub site structure.
Use Search Schema Best Practices
Do not map every column as a managed property. Only map columns that users need to search or filter by. Each managed property adds overhead to the index. For columns that are rarely used for search, leave them unmapped. This reduces crawl time and improves search relevance.
If Reindexing Does Not Fix Search Problems
Search Results Still Missing After 24 Hours
If you reindexed a library and search results are still incomplete after 24 hours, the problem may be permission-based. SharePoint search respects item-level permissions. If a user does not have read access to a file, that file does not appear in their search results. Check the permissions on missing files. Also verify that the user has at least read access to the library.
Filters Show Incorrect Values
Filter dropdowns in a document library use the search index, not the live data. If a metadata column was recently changed but the filter still shows old values, reindexing usually fixes it. However, if the column uses a term set from the term store, ensure the term set is published. Unpublished terms are not indexed. Go to Term store management and check the status of the term set.
Reindex Button Does Not Appear
The Reindex Document Library button is only visible to site owners and users with full control permissions. If you do not see the button, ask a site owner to perform the reindex. Alternatively, a SharePoint admin can use PowerShell to trigger reindexing. Run the command Request-SPOPageReindex -ListTitle "Your Library Name" after connecting to SharePoint Online via PnP PowerShell.
Document Library Reindexing vs Full Site Reindexing
| Item | Reindex Document Library | Reindex Entire Site |
|---|---|---|
| Scope | Single list or library | All lists, libraries, and pages in the site collection |
| Permissions needed | Library owner or full control | Site owner or full control |
| Impact on search service | Low to moderate | High |
| Time to complete | 15 minutes to 4 hours | 1 hour to 24 hours |
| When to use | One library has outdated metadata or missing files | Multiple libraries are broken or site-level search is inaccurate |
Reindexing a single library is the preferred method for most search issues because it limits the load on the search service. Use the site-level reindex only when problems affect multiple libraries or when the site’s search results are generally unreliable.
You can now reindex a SharePoint document library using the correct button in Library settings and apply the best search settings for Microsoft 365. After reindexing, verify that managed metadata columns are mapped and that the library item count stays under 500,000. For persistent search issues, check item-level permissions and publish term sets in the term store. An advanced step is to use PowerShell to request a reindex and monitor the crawl log in the SharePoint admin center for errors.