diff --git a/nixos/modules/virtualisation/libvirtd.nix b/nixos/modules/virtualisation/libvirtd.nix
index 552441f6a62..d8668eb1607 100644
--- a/nixos/modules/virtualisation/libvirtd.nix
+++ b/nixos/modules/virtualisation/libvirtd.nix
@@ -101,6 +101,19 @@ in
                 mkdir -p /etc/$(dirname $i) -m 755
                 cp -fpd ${pkgs.libvirt}/etc/$i /etc/$i
             done
+
+            # libvirtd puts the full path of the emulator binary in the machine
+            # config file. But this path can unfortunately be garbage collected
+            # while still being used by the virtual machine. So update the
+            # emulator path on each startup to something valid (re-scan $PATH).
+            for file in /etc/libvirt/qemu/*.xml; do
+                # get (old) emulator path from config file
+                emulator=$(grep "^[[:space:]]*<emulator>" "$file" | sed 's,^[[:space:]]*<emulator>\(.*\)</emulator>.*,\1,')
+                # get a (definitely) working emulator path by re-scanning $PATH
+                new_emulator=$(command -v $(basename "$emulator"))
+                # write back
+                sed -i "s,^[[:space:]]*<emulator>.*,    <emulator>$new_emulator</emulator> <!-- WARNING: emulator dirname is auto-updated by the nixos libvirtd module -->," "$file"
+            done
           ''; # */
 
         serviceConfig.ExecStart = ''@${pkgs.libvirt}/sbin/libvirtd libvirtd --config "${configFile}" --daemon --verbose'';