Garmin Express caches downloaded map data at:
%LOCALAPPDATA%\Garmin\express\maps
This can silently grow to 10+ GB with no warning and no in-app setting to relocate it. Garmin's own support site confirms there's no supported way to change this path ("Unable to Change the Installation Location of a Map Update in Garmin Express for Windows").
Check current size:
$g = "$env:LOCALAPPDATA\Garmin\express\maps"
if (Test-Path $g) { (Get-ChildItem $g -Recurse -Force -ErrorAction SilentlyContinue | Measure-Object Length -Sum).Sum/1GB } else { "Not present" }
Prerequisite — you need a second drive or partition. The fix below redirects the cache to a drive letter other than C:. If your system only has a single C: partition (very common — most consumer PCs ship this way), you'll need to create one first. This does not move or affect your existing Windows installation — Windows and all your programs stay exactly where they are on C:. You're simply shrinking C: to free up unused space at the end of the drive, then formatting that freed space as a new partition with its own drive letter (e.g., D:).
Official Microsoft documentation covering this (built into Windows, no third-party tools needed): support.microsoft.com/.../disk-management-in-windows-ad88ba19-f0d3-0809-7889-830f63e94405
Short version: open Disk Management (right-click Start → Disk Management), right-click your C: volume → Shrink Volume, enter how much space to free (in MB), then right-click the resulting "Unallocated" space → New Simple Volume and follow the wizard to format it and assign a drive letter. This is non-destructive to existing data, but backing up first is always good practice before any partition change.
Fix — redirect via NTFS directory junction (works because Garmin Express only knows the AppData path, not the physical location):
- Close Garmin Express completely first.
- Move existing cache contents and create the junction (adjust D: to whatever drive letter you created):
robocopy "%LOCALAPPDATA%\Garmin\express\maps" "D:\GarminCache\maps" /E /MOVE
mklink /J "%LOCALAPPDATA%\Garmin\express\maps" "D:\GarminCache\maps"
If the maps folder doesn't exist yet (fresh install, nothing cached), skip robocopy and just do:
mkdir "D:\GarminCache\maps"
mklink /J "%LOCALAPPDATA%\Garmin\express\maps" "D:\GarminCache\maps"
- Verify the junction is live:
dir "%LOCALAPPDATA%\Garmin\express"
maps should show as <JUNCTION> rather than a normal folder.
From this point on, all Garmin Express map caching writes transparently through to the new drive — no further action needed, and Garmin Express has no idea anything changed.
