diff --git a/lib/images/windows/helpers/customizeImage.nix b/lib/images/windows/helpers/customizeImage.nix
index a1e7be8..51b4d30 100644
--- a/lib/images/windows/helpers/customizeImage.nix
+++ b/lib/images/windows/helpers/customizeImage.nix
@@ -99,7 +99,11 @@
       VMIX_DISPLAY="-nographic"
       ${lib.optionalString (vncDisplay != null) ''VMIX_DISPLAY="-vnc ${vncDisplay}"''}
       ${lib.optionalString (vncDisplay == null) ''
-        VMIX_DF=$(ls -t /tmp/.vmix-display-* 2>/dev/null | head -1)
+        # find, not a glob: under nullglob a non-matching /tmp/.vmix-display-*
+        # disappears entirely, leaving `ls -t` to list the build directory and
+        # hand back nix's own env-vars dump. Exporting that as DISPLAY bloats
+        # the environment until every exec dies with E2BIG.
+        VMIX_DF=$(find /tmp -maxdepth 1 -type f -name '.vmix-display-*' -printf '%T@ %p\n' 2>/dev/null | sort -rn | head -1 | cut -d' ' -f2-)
         if [ -n "$VMIX_DF" ]; then
           export DISPLAY=$(sed -n '1p' "$VMIX_DF")
           export XAUTHORITY=$(sed -n '2p' "$VMIX_DF")
diff --git a/lib/images/windows/helpers/makeImage.nix b/lib/images/windows/helpers/makeImage.nix
index 983c6fb..0f16750 100644
--- a/lib/images/windows/helpers/makeImage.nix
+++ b/lib/images/windows/helpers/makeImage.nix
@@ -49,7 +49,11 @@ let
     VMIX_DISPLAY="-nographic"
     ${lib.optionalString (displayArg != null) ''VMIX_DISPLAY="${displayArg}"''}
     ${lib.optionalString (displayArg == null) ''
-      VMIX_DF=$(ls -t /tmp/.vmix-display-* 2>/dev/null | head -1)
+      # find, not a glob: under nullglob a non-matching /tmp/.vmix-display-*
+      # disappears entirely, leaving `ls -t` to list the build directory and
+      # hand back nix's own env-vars dump. Exporting that as DISPLAY bloats the
+      # environment until every exec dies with E2BIG.
+      VMIX_DF=$(find /tmp -maxdepth 1 -type f -name '.vmix-display-*' -printf '%T@ %p\n' 2>/dev/null | sort -rn | head -1 | cut -d' ' -f2-)
       if [ -n "$VMIX_DF" ]; then
         export DISPLAY=$(sed -n '1p' "$VMIX_DF")
         export XAUTHORITY=$(sed -n '2p' "$VMIX_DF")