diff --git a/internal/assertions/assertions.go b/internal/assertions/assertions.go
index fa24d0f..53e8f17 100644
--- a/internal/assertions/assertions.go
+++ b/internal/assertions/assertions.go
@@ -959,11 +959,16 @@ func FileExistsFS(system fs.FS, file string) (s string) {
 
 func FileNotExistsFS(system fs.FS, file string) (s string) {
 	_, err := fs.Stat(system, file)
-	if !errors.Is(err, fs.ErrNotExist) {
+	if err == nil {
 		s = "expected file to not exist\n"
 		s += bullet("name: %s\n", file)
 		return
 	}
+	if !errors.Is(err, fs.ErrNotExist) {
+		s = "expected not existing file but got different error\n"
+		s += bullet("error: %s\n", err)
+		return
+	}
 	return
 }
 
diff --git a/must/must.go b/must/must.go
index 3fb4056..67d2199 100644
--- a/must/must.go
+++ b/must/must.go
@@ -5,6 +5,7 @@ package must
 import (
 	"io/fs"
 	"os"
+	"path/filepath"
 	"regexp"
 	"strings"
 
@@ -521,7 +522,9 @@ func FileNotExistsFS(t T, system fs.FS, file string, settings ...Setting) {
 // FileNotExists asserts file does not exist on the OS filesystem.
 func FileNotExists(t T, file string, settings ...Setting) {
 	t.Helper()
-	invoke(t, assertions.FileNotExistsFS(os.DirFS(brokenfs.Root), file), settings...)
+	dir := filepath.Dir(file)
+	file = filepath.Base(file)
+	invoke(t, assertions.FileNotExistsFS(os.DirFS(dir), file), settings...)
 }
 
 // DirExistsFS asserts directory exists on the fs.FS filesystem.
diff --git a/test.go b/test.go
index 316abfc..4c97ef1 100644
--- a/test.go
+++ b/test.go
@@ -3,6 +3,7 @@ package test
 import (
 	"io/fs"
 	"os"
+	"path/filepath"
 	"regexp"
 	"strings"
 
@@ -519,7 +520,9 @@ func FileNotExistsFS(t T, system fs.FS, file string, settings ...Setting) {
 // FileNotExists asserts file does not exist on the OS filesystem.
 func FileNotExists(t T, file string, settings ...Setting) {
 	t.Helper()
-	invoke(t, assertions.FileNotExistsFS(os.DirFS(brokenfs.Root), file), settings...)
+	dir := filepath.Dir(file)
+	file = filepath.Base(file)
+	invoke(t, assertions.FileNotExistsFS(os.DirFS(dir), file), settings...)
 }
 
 // DirExistsFS asserts directory exists on the fs.FS filesystem.