845: Time-out occurred while waiting for buffer latch

What does it mean?

A timeout occurred while waiting for a buffer latch on a data page. SQL Server could not acquire the short-lived internal lock (latch) needed to access a page in a reasonable time; usually a sign of heavy I/O or memory pressure.

Why does it happen?

A slow/overloaded disk subsystem, pages constantly read from disk due to memory pressure, hardware problems, excessive paging, or a storage bottleneck.

How to fix it

Measure disk I/O latency (sys.dm_io_virtual_file_stats, Perfmon disk latency). Check storage performance and hardware health. Review memory sufficiency and the max server memory setting. Examine wait types (sys.dm_os_wait_stats, PAGEIOLATCH waits). Remove the storage bottleneck; provide faster disks/more RAM if needed.