diff --git a/extensions/markdown-language-features/src/preview/preview.ts b/extensions/markdown-language-features/src/preview/preview.ts
index 26f94614ad8..51348bd7128 100644
--- a/extensions/markdown-language-features/src/preview/preview.ts
+++ b/extensions/markdown-language-features/src/preview/preview.ts
@@ -158,7 +158,7 @@ class MarkdownPreview extends Disposable implements WebviewResourceProvider {
 		this._register(watcher.onDidChange(uri => {
 			if (this.isPreviewOf(uri)) {
 				// Only use the file system event when VS Code does not already know about the file
-				if (!vscode.workspace.textDocuments.some(doc => doc.uri.toString() !== uri.toString())) {
+				if (!vscode.workspace.textDocuments.some(doc => doc.uri.toString() === uri.toString())) {
 					this.refresh();
 				}
 			}