After delving into the intricacies of the search index on a fresh installation of Windows 11, I discovered that the initial cost in terms of storage was minimal—merely a few megabytes. However, upon introducing a sizable work folder into the mix, the index expanded as anticipated. Yet, an interesting phenomenon occurred: once I removed that folder, the index did not revert to its previous size.
This index serves as the backbone of the search functionality, facilitating quick access to applications and files through the Start menu. The data is housed in Windows.db for Windows 11 users and Windows.edb for those still on Windows 10. Unfortunately, this database can swell to problematic proportions.
What Windows indexes by default, and what it reads from it
Windows 11 provides two indexing modes: Classic and Enhanced. The Classic mode, which is the default setting, encompasses your Documents, Pictures, Music folders, and the Desktop. In contrast, Enhanced mode scans the entire PC.
It’s important to note that Windows does not limit its indexing to mere file names. When files contain text, their content is also indexed, allowing for keyword searches within the files themselves. Since the indexing scope is location-based rather than volume-based, anything placed in the Documents folder becomes part of the index. This includes everything from a few cover letters to extensive project folders containing thousands of files.
Users typically fall into one of three categories: those who have opted for Enhanced mode, those whose Documents folder is linked to OneDrive or another synced directory, and those who store large projects or virtual machines within Documents. If you don’t identify with any of these groups, rest assured that your indexing experience is likely smooth sailing.
Measuring your index in two easy steps
To assess the number of items in your index, no special permissions are required. Simply navigate to Settings, then Privacy and security, followed by Search. The “Indexed” counter is conveniently located at the top of the page, where you can also adjust the indexing scope.
However, determining the file size necessitates administrative access. Launch PowerShell as an administrator and enter the following command:
[math]::Round((Get-Item "$env:ProgramDataMicrosoftSearchDataApplicationsWindowsWindows.db" -Force).Length / 1MB, 2)This will yield a size in megabytes. Yet, it is the item counter that truly indicates whether the index is excessively large, rather than the size itself. Microsoft provides some benchmarks: an index under 30,000 items is generally acceptable for average users, while heavy users may not bat an eye at 300,000 items. However, performance issues can arise beyond 400,000 items, and the technical ceiling is set at one million items, beyond which the indexer may falter, causing spikes in CPU, memory, and disk utilization.
The test: 3,000 files leave, an index stays
In a controlled experiment conducted within a Windows 11 Pro 25H2 virtual machine, equipped with four cores and 8 GB of RAM, I began with 462 indexed items totaling 6.71 MB. After adding 3,000 text files, which amounted to 15.94 MB, the index rose to 3,466 items, with the database size increasing to 18.66 MB. This scenario illustrates a critical point: the index can grow almost to match the size of the files it ingests, particularly when dealing with plain text, which requires comprehensive indexing.
Upon deleting the 3,000 files, the item count returned to 465, but the Windows.db file size remained at 16.81 MB. This indicates that while the index purged its entries, it retained the allocated space for future use.
Taking back control without breaking search
To reclaim disk space, targeted exclusion is the most effective strategy. Navigate to Settings, Privacy and security, Search, and select ” Add an excluded folder.” Ideal candidates for exclusion include frequently changing directories or those that are not valuable for search purposes, such as project dependency folders, build directories, caches, virtual machine disks, .git folders, and game libraries.
After making exclusions, you can verify their effectiveness by checking the “Indexed” counter again; it should decrease by the number of files in the excluded folder without requiring further action.
It’s crucial to avoid excluding the entire Documents or Desktop folders, and certainly do not disable the indexing service altogether. The Start menu relies on this index for efficient searching, and excluding a folder would render its contents invisible to search queries, potentially complicating tasks like locating emails in Outlook.
As a final step, consider rebuilding the index to reclaim space effectively. Access Advanced Indexing Options from the same settings page, click on Advanced, and then select Rebuild in the Troubleshooting section. Windows will caution that search results may be incomplete during this process, which is entirely expected as the index is rebuilt from scratch. Microsoft recommends allowing the indexer up to 24 hours to complete its work, so timing is key.
In my case, the index, which had ballooned to 16.81 MB, was reduced to just 1 MB after four minutes of rebuilding, while still retaining the same 465 items. Afterward, running the PowerShell command again revealed whether the index was already at an optimal size or if the disk space issue lay elsewhere.
