diff --git a/backend/local/local.go b/backend/local/local.go
index 887c66725..d785fee85 100644
--- a/backend/local/local.go
+++ b/backend/local/local.go
@@ -1213,7 +1213,7 @@ func (f *Fs) OpenWriterAt(ctx context.Context, remote string, size int64) (fs.Wr
 		// Set the file to be a sparse file (important on Windows)
 		err = file.SetSparse(out)
 		if err != nil {
-			fs.Debugf(o, "Failed to set sparse: %v", err)
+			fs.Errorf(o, "Failed to set sparse: %v", err)
 		}
 	}
 
diff --git a/vfs/help.go b/vfs/help.go
index d191b9a17..7e34e6038 100644
--- a/vfs/help.go
+++ b/vfs/help.go
@@ -166,6 +166,11 @@ whereas the --vfs-read-ahead is buffered on disk.
 When using this mode it is recommended that --buffer-size is not set
 too big and --vfs-read-ahead is set large if required.
 
+**IMPORTANT** not all file systems support sparse files. In particular
+FAT/exFAT do not. Rclone will perform very badly if the cache
+directory is on a filesystem which doesn't support sparse files and it
+will log an ERROR message if one is detected.
+
 ### VFS Performance
 
 These flags may be used to enable/disable features of the VFS for
diff --git a/vfs/vfscache/item.go b/vfs/vfscache/item.go
index 1606237ff..e828b9cb8 100644
--- a/vfs/vfscache/item.go
+++ b/vfs/vfscache/item.go
@@ -249,7 +249,7 @@ func (item *Item) _truncate(size int64) (err error) {
 
 		err = file.SetSparse(fd)
 		if err != nil {
-			fs.Debugf(item.name, "vfs cache: truncate: failed to set as a sparse file: %v", err)
+			fs.Errorf(item.name, "vfs cache: truncate: failed to set as a sparse file: %v", err)
 		}
 	}
 
@@ -446,7 +446,7 @@ func (item *Item) _createFile(osPath string) (err error) {
 	}
 	err = file.SetSparse(fd)
 	if err != nil {
-		fs.Debugf(item.name, "vfs cache: failed to set as a sparse file: %v", err)
+		fs.Errorf(item.name, "vfs cache: failed to set as a sparse file: %v", err)
 	}
 	item.fd = fd