Windows.edb larger than expected when a PST file is indexed in Windows

S’applique à : Windows 10, version 1809Windows 10Windows 8.1

Symptoms


When you index a PST file from Control Panel -> Indexing options, the size of the Windows.edb file (which is located under %ProgramData%\Microsoft\Search\Data\Applications\Windows) grows in proportion to the size of the PST file.

This issue can result in low disk space and other performance issues.

This issue doesn't occur on Windows 7.

Cause


There are two reasons why Windows.edb is larger on Windows 8, Windows 8.1 and Windows 10 than on Windows 7:

  • Both properties and persistent indexes are stored in Windows.edb starting with Windows 8. On Windows 7, only properties are stored in Windows.edb—persistent indexes are stored separately, in *.ci files.  
  • Windows 8, Windows 8.1 and Windows 10 indexes the entire contents of files, regardless of their size. Windows 7 indexes only the first part of large documents.

Neither of these behaviors is configurable on Windows 8, Windows 8.1 or Windows 10. This behavior improves recall for searches and general performance of indexing and querying.

Resolution


To work around this issue, follow these steps:

  1. Index less content. If you have a lot of content, Windows.edb can be expected to grow very large. In this case, the only option to reduce disk usage is to index less content locally (by having Outlook cache less mail locally or by changing scopes in Indexing Options -> Modify, followed by rebuilding the index from Advanced -> Rebuild).
  2. Run an offline defrag of the .edb file from a command prompt by running the following commands:
    Sc config wsearch start=disableNet stop wsearchEsentUtl.exe /d %AllUsersProfile%\Microsoft\Search\Data\Applications\Windows\Windows.edbSc config wsearch start=delayed-autoNet start wsearch