diff --git a/code/qcommon/cm_patch.c b/code/qcommon/cm_patch.c
index 3a4e37cc..3cd7bcaf 100644
--- a/code/qcommon/cm_patch.c
+++ b/code/qcommon/cm_patch.c
@@ -607,7 +607,7 @@ static int	CM_GridPlane( int gridPlanes[MAX_GRID_SIZE][MAX_GRID_SIZE][2], int i,
 	}
 
 	// should never happen
-	Com_Error( ERR_DROP, "CM_GridPlane unresolvable" );
+	Com_Printf( "WARNING: CM_GridPlane unresolvable\n" );
 	return -1;
 }
 
@@ -626,6 +626,9 @@ static int CM_EdgePlaneNum( cGrid_t *grid, int gridPlanes[MAX_GRID_SIZE][MAX_GRI
 		p1 = grid->points[i][j];
 		p2 = grid->points[i+1][j];
 		p = CM_GridPlane( gridPlanes, i, j, 0 );
+		if ( p == -1 ) {
+			return -1;
+		}
 		VectorMA( p1, 4, planes[ p ].plane, up );
 		return CM_FindPlane( p1, p2, up );
 
@@ -633,6 +636,9 @@ static int CM_EdgePlaneNum( cGrid_t *grid, int gridPlanes[MAX_GRID_SIZE][MAX_GRI
 		p1 = grid->points[i][j+1];
 		p2 = grid->points[i+1][j+1];
 		p = CM_GridPlane( gridPlanes, i, j, 1 );
+		if ( p == -1 ) {
+			return -1;
+		}
 		VectorMA( p1, 4, planes[ p ].plane, up );
 		return CM_FindPlane( p2, p1, up );
 
@@ -640,6 +646,9 @@ static int CM_EdgePlaneNum( cGrid_t *grid, int gridPlanes[MAX_GRID_SIZE][MAX_GRI
 		p1 = grid->points[i][j];
 		p2 = grid->points[i][j+1];
 		p = CM_GridPlane( gridPlanes, i, j, 1 );
+		if ( p == -1 ) {
+			return -1;
+		}
 		VectorMA( p1, 4, planes[ p ].plane, up );
 		return CM_FindPlane( p2, p1, up );
 
@@ -647,6 +656,9 @@ static int CM_EdgePlaneNum( cGrid_t *grid, int gridPlanes[MAX_GRID_SIZE][MAX_GRI
 		p1 = grid->points[i+1][j];
 		p2 = grid->points[i+1][j+1];
 		p = CM_GridPlane( gridPlanes, i, j, 0 );
+		if ( p == -1 ) {
+			return -1;
+		}
 		VectorMA( p1, 4, planes[ p ].plane, up );
 		return CM_FindPlane( p1, p2, up );
 
@@ -654,6 +666,9 @@ static int CM_EdgePlaneNum( cGrid_t *grid, int gridPlanes[MAX_GRID_SIZE][MAX_GRI
 		p1 = grid->points[i+1][j+1];
 		p2 = grid->points[i][j];
 		p = CM_GridPlane( gridPlanes, i, j, 0 );
+		if ( p == -1 ) {
+			return -1;
+		}
 		VectorMA( p1, 4, planes[ p ].plane, up );
 		return CM_FindPlane( p1, p2, up );
 
@@ -661,6 +676,9 @@ static int CM_EdgePlaneNum( cGrid_t *grid, int gridPlanes[MAX_GRID_SIZE][MAX_GRI
 		p1 = grid->points[i][j];
 		p2 = grid->points[i+1][j+1];
 		p = CM_GridPlane( gridPlanes, i, j, 1 );
+		if ( p == -1 ) {
+			return -1;
+		}
 		VectorMA( p1, 4, planes[ p ].plane, up );
 		return CM_FindPlane( p1, p2, up );