diff --git a/CHANGELOG.md b/CHANGELOG.md
index 97c04335..f85ccf83 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+- Files: opening a file over 5,000 lines is no longer blocked — the line-count guard now allows up to 20,000 lines, letting large files reach the virtualized full-file preview instead of being rejected at the open step (thanks @gaojunran).
 - Settings: fixed the Cloudflare Tunnel download link shown when cloudflared is not installed (thanks to @AyoubAchour).
 
 ## [1.21.0] - 2026-08-26
diff --git a/packages/ui/src/lib/fileOpenLimits.ts b/packages/ui/src/lib/fileOpenLimits.ts
index d4d1504c..734af429 100644
--- a/packages/ui/src/lib/fileOpenLimits.ts
+++ b/packages/ui/src/lib/fileOpenLimits.ts
@@ -1,4 +1,4 @@
-export const MAX_OPEN_FILE_LINES = 5_000;
+export const MAX_OPEN_FILE_LINES = 20_000;
 
 export const countLinesWithLimit = (content: string, limit: number): number => {
   if (!content) {