TortoiseSVN and TortoiseGit use the TSVNCache.exe to collect all update notifications and update the status overlay icons in one place. This provides real-time updates and improves latency when showing folders in the explorer.

On the downside, TSVNCache is easily confused by subst.exe since it’ll receive updates only for one of the locations. The TortoiseGIT documentation provides this work-around:

[...] exclude the original path from showing overlays, so that the overlays show up on the subst path instead.

We use subst to have a default “project drive” located at P:, therefore I disabled updates for all drive types and only set the “Included Paths” option to “P:\”.