SMB Activity on Windows 11 Desktop Start-Up

I have a fairly simple home setup with a DS918+ attached to my network via 1GbE. Whenever I start my Windows 11 desktop, the NAS disk activity runs through the roof for 5-10 minutes making access slow. Looking on DSM it appears it’s SMB. What is it doing (is it indexing) and is there a fix to minimise this issue?