pagefile.sys (page file)

pagefile.sys is a hidden system file, by default in the root of the Windows drive, that Windows uses as an extension of physical memory. Rarely used memory pages are moved to it, and it is needed to record crash dumps. By default Windows manages its size automatically.

1Why it matters

The page file raises the commit limit, the total amount of memory that programs can reserve. Without it, programs can fail with out-of-memory errors even when some RAM appears free.

When Windows stops with a blue screen, the memory dump is written through the page file. Without a page file of sufficient size, no dump is created and the cause is harder to find.

2Size

With 'Automatically manage paging file size for all drives', Windows chooses the size based on memory, crash-dump settings and actual use, and can grow it when needed. The file can also be placed on another drive or given a fixed size.

How to check the page file settings

1. Press Win+R, type sysdm.cpl and press Enter.
2. Open Advanced > Performance > Settings > Advanced > Virtual memory > Change.
3. Check whether 'Automatically manage paging file size for all drives' is selected.
4. Leave automatic management on unless you have a specific reason to change it.

Related articles

• hiberfil.sys (hibernation file)What hiberfil.sys is, why it is so large, how Fast Startup uses it, and how to shrink or remove it with powercfg.
• Temporary files in WindowsWhere Windows keeps temporary files (%TEMP%, C:\Windows\Temp), what is safe to delete and the supported ways to clean them.
• Event ViewerHow to read Windows event logs in Event Viewer, which logs matter for crashes and errors, and how to export or clear them.

Sources

1. Introduction to the page file (Microsoft Learn) learn.microsoft.com
2. How to determine the appropriate page file size for 64-bit versions of Windows (Microsoft Learn) learn.microsoft.com

Last reviewed: 2026-10-08