# Unhandled ArgumentException after auto-save when another plugin closes/reopens the database

**URL:** <https://forum.kee.pm/t/unhandled-argumentexception-after-auto-save-when-another-plugin-closes-reopens-the-database/5148>\
**Category:** Kee browser extension\
**Created:** [October 3, 2026, 2:07am UTC](https://forum.kee.pm/t/unhandled-argumentexception-after-auto-save-when-another-plugin-closes-reopens-the-database/5148 "2026-10-03T02:07:44Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![YoNevelt](https://forum.kee.pm/user_avatar/forum.kee.pm/yonevelt/32/1246_2.png) [@YoNevelt](https://forum.kee.pm/u/YoNevelt)\
**Post date:** [October 3, 2026, 2:07am UTC](https://forum.kee.pm/t/unhandled-argumentexception-after-auto-save-when-another-plugin-closes-reopens-the-database/5148/1 "2026-10-03T02:07:44Z")

</div>

**Title:** Unhandled ArgumentException after auto-save when another plugin closes/reopens the database (KeePassRPC 2.0.2)

**Summary**

When Kee adds or updates an entry and KeePassRPC auto-saves the database, KeePass occasionally shows an unhandled exception dialog:

```auto
System.ArgumentException: Value does not fall within the expected range.
   at KeePass.UI.DocumentManagerEx.set_ActiveDocument(PwDocument value)

```

The save itself completes; clicking Continue lets KeePass carry on.

**Environment**

- KeePass 2.61.1 (installed, 64-bit), Windows 11, .NET Framework 4.8.1
- KeePassRPC 2.0.2
- KeePassMasterSlaveSync 0.99 also installed
- Browser / Kee extension version: [fill in]

**Steps to reproduce**

1. Install KeePassRPC 2.0.2 and KeePassMasterSlaveSync 0.99.
2. Open a database that has an `MSSyncJobs` group with at least one enabled sync job. Leave KeePassRPC’s auto-save setting on (the default).
3. In the browser, let Kee save a new login or update an existing one.
4. KeePass shows the exception dialog above.

**Cause (from reading the source, not from a debugger)**

`saveDB` in `KeePassRPC/KeePassRPCService.cs` stores the active `PwDocument`, calls `UIFileSave`, and then assigns the stored document back to `DocumentManager.ActiveDocument`.

`UIFileSave` raises `FileSaved`. KeePassMasterSlaveSync handles that event and, after running its jobs, calls `DocumentManager.CloseDatabase(...)` followed by `MainForm.OpenDatabase(...)` for the affected databases, including the master. That removes the original `PwDocument` from the document list and creates a new one.

When `saveDB` then assigns the stale document, the `ActiveDocument` setter throws `ArgumentException` because the value is not in its list. `saveDB` is queued with `MainWindow.BeginInvoke`, so nothing catches it and it surfaces as the WinForms unhandled exception dialog.

This is not specific to that plugin: anything that closes the document during the save would have the same effect. I’d expect a KeePass trigger on “Saved database file” with the action “Close active database” to reproduce it too, but I have not tested that.

**Proposed fix**

Only restore the previous tab if it still exists:

```diff
--- a/KeePassRPC/KeePassRPCService.cs
+++ b/KeePassRPC/KeePassRPCService.cs
@@ -158,8 +158,12 @@
                 _host.MainWindow.UpdateUI(false, null, true, null, true, null, true);
             }
 
- // change tab back
- _host.MainWindow.DocumentManager.ActiveDocument = currentActiveDoc;
+ // change tab back, unless that tab no longer exists. A FileSaved handler
+ // (e.g. another plugin that closes and reopens the database after a save)
+ // can replace the PwDocument while UIFileSave runs; assigning a document
+ // that is no longer in the list makes KeePass throw an ArgumentException.
+ if (_host.MainWindow.DocumentManager.Documents.Contains(currentActiveDoc))
+ _host.MainWindow.DocumentManager.ActiveDocument = currentActiveDoc;
         }
 
         private void openGroupEditorWindow(PwGroup pg, PwDatabase db)

```

I’m running a local build of 2.0.2 with this change. Happy to open a pull request if that’s useful.