> For the complete documentation index, see [llms.txt](https://docs.devolutions.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.devolutions.net/rdm/knowledge-base/troubleshooting-articles/clipboard-diagnostic.md).

# Clipboard diagnostic

This article helps you diagnose clipboard issues in Remote Desktop Manager; copies that fail to paste, values that disappear too quickly, or applications that behave inconsistently between browsers.

Use this list to go directly to the section that matches your symptom. If multiple symptoms seem to apply, start with the first one that matches.

* **Paste into a browser does nothing** (but works in another browser). See [Null requester check](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#null-requester-check).
* **Paste works once, then stops**. See [Paste Once and delays](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#paste-once-and-delays).
* **The clipboard clears itself after a few seconds**. See [Clear clipboard delay](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#clear-clipboard-delay).
* **A specific application keeps reading the clipboard**. See [Blocklist management](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#blocklist-management).
* **The clipboard appears blank immediately after copy**. See [How to read the profiler](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#how-to-read-the-profiler).

### Test in 30 seconds <a href="#test-in-30-seconds" id="test-in-30-seconds"></a>

Before changing any settings, confirm where the problem is by running this fast test:

1. In Remote Desktop Manager, copy a credential (or any entry value) to the clipboard.
2. Open Notepad and press <kbd>Ctrl</kbd>+<kbd>V</kbd>.
   * If the value pastes correctly, Remote Desktop Manager is copying fine. The problem is with the target application's clipboard read.
   * If nothing pastes, Remote Desktop Manager is not publishing the value. Continue with [How to read the profiler](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#how-to-read-the-profiler).
3. Open the target application (for example Chrome) and press <kbd>Ctrl</kbd>+<kbd>V</kbd> in a text field.
   * If it works, no further action is needed.
   * If nothing pastes, you most likely hit the [Null requester check](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#null-requester-check).
4. Optional: repeat step 3 in a second browser (for example Microsoft Edge). If it works in one browser but not the other, this confirms the null requester check is the cause.

### Null requester check <a href="#null-requester-check" id="null-requester-check"></a>

Remote Desktop Manager refuses to hand clipboard data to any process that does not identify itself with a visible window. This protects your credentials from invisible or background processes that try to read the clipboard silently.

In the clipboard profiler, a blocked request appears as:

```
Clipboard - Render - Requester : 0 - Format : 13
```

`Requester : 0` means the requesting process did not provide a window handle.

#### Known applications that trigger this protection <a href="#known-applications-that-trigger-this-protection" id="known-applications-that-trigger-this-protection"></a>

* Recent versions of Google Chrome (clipboard reads issued from a background renderer thread).
* Some Electron-based applications.
* Certain clipboard manager and automation tools.

Microsoft Edge and most native Windows applications are not affected; they request the clipboard with a proper window handle.

#### How to allow these applications <a href="#how-to-allow-these-applications" id="how-to-allow-these-applications"></a>

Disabling this check lowers protection against background processes reading clipboard data. Only disable it on machines where you trust the running applications.

1. Go to ***File*** – ***Settings*** – ***Application*** – ***Clipboard*** – ***Advanced***.
2. Enable ***Disable clipboard null requester check***.
3. Click ***OK*** and retry the copy and paste.

#### If you want to keep the protection <a href="#if-you-want-to-keep-the-protection" id="if-you-want-to-keep-the-protection"></a>

Instead of disabling the check, choose one of the following:

* Paste into Microsoft Edge or another browser that uses a visible window handle.
* Use the separate ***Copy username*** and ***Copy password*** actions from the entry's context menu and paste immediately.
* Paste into a native field (for example Notepad) first, then copy from there into the target application.

### How to read the profiler <a href="#how-to-read-the-profiler" id="how-to-read-the-profiler"></a>

The clipboard profiler logs every step of a copy and paste cycle. The table below maps the most common lines to their meaning and the recommended action.

| Log line                                     | Description                                                                 | Action                                                                                                                               |
| -------------------------------------------- | --------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `Render - Requester : 0 - Format : 13`       | A process requested the clipboard without a visible window and was blocked. | See [Null requester check](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#null-requester-check). |
| `Render - Blocked - Requester: <hwnd>`       | The requesting process is on the blocklist.                                 | Remove it from the blocklist if it is trusted.                                                                                       |
| `Render - Allow listed - Requester : <hwnd>` | The requesting process is on the allowlist and has been served.             | No action.                                                                                                                           |
| `Paste Once - Count : N`                     | The clipboard payload may be read `N` times before being cleared.           | If pastes are being consumed by background reads, raise the count or switch to the ***Legacy*** copy method.                         |
| `Promise - Format : <id>`                    | The clipboard is advertising a format for delayed render. This is normal.   | No action.                                                                                                                           |
| `Empty` immediately after copy               | The honeypot or clear delay cleared the clipboard.                          | Review the honeypot list and the clear clipboard delay value.                                                                        |
| `Clear`                                      | The clipboard was cleared by a timer, paste-once exhaustion, or honeypot.   | Check which mechanism is active in ***File*** – ***Settings*** – ***Application*** – ***Clipboard*** – ***Advanced***.               |

#### Common format IDs <a href="#common-format-ids" id="common-format-ids"></a>

| Format ID                                   | Description                                                                                                                                                                                                                                                                                                      |
| ------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `13`                                        | `CF_UNICODETEXT` — the pasted text itself.                                                                                                                                                                                                                                                                       |
| `49924`, `49925`, `49930`, `50004`, `50005` | <p>Represents private formats advertised by Remote Desktop Manager as definied by Microsoft and others.<br></p><ul><li>Clipboard Viewer Ignore</li><li>CanIncludeInClipboardHistory</li><li>CanUploadToCloudClipboard</li><li>ExcludeClipboardContentFromMonitorProcessing</li><li>RDMClipboardContent</li></ul> |

### Paste Once and delays <a href="#paste-once-and-delays" id="paste-once-and-delays"></a>

***Paste Once*** is a clipboard copy method that clears the clipboard after a configured number of paste operations, to prevent the credential from lingering in the clipboard history.

#### How it works <a href="#how-it-works" id="how-it-works"></a>

* The clipboard advertises the copied value to Windows.
* Each time a process reads the clipboard, the ***Paste Once*** counter decrements.
* When the counter reaches zero, Remote Desktop Manager clears the clipboard.

#### When to adjust it <a href="#when-to-adjust-it" id="when-to-adjust-it"></a>

Some applications read the clipboard multiple times for a single paste to preview content, populate the paste menu, or sync with cloud clipboard services.

These background reads consume ***Paste Once*** counts before you actually paste.

Symptoms:

* The first paste works, but the value is cleared too quickly to paste a second time.
* The profiler shows multiple `Render - Requester : <hwnd>` lines before your explicit paste.

#### How to adjust <a href="#how-to-adjust" id="how-to-adjust"></a>

1. Go to ***File*** – ***Settings*** – ***Application*** – ***Clipboard*** – ***Advanced***.
2. Do one of the following:
   * Increase the ***Paste Once count*** so background reads do not exhaust the allowance before your paste.
   * Switch ***Clipboard copy method*** to ***Legacy*** (the classic Windows clipboard, with no paste-once protection).

#### Per-process delays <a href="#per-process-delays" id="per-process-delays"></a>

For some applications, a better option is to add a per-process delay so Remote Desktop Manager waits before publishing the value:

1. Open the ***Clipboard diagnostic*** window from the ***Help*** menu.
2. In the ***Configuration*** tab, add a delay entry for the target application.
3. A value between ***150 ms*** and ***500 ms*** works for most browsers.

### Clear clipboard delay <a href="#clear-clipboard-delay" id="clear-clipboard-delay"></a>

Remote Desktop Manager can automatically clear the clipboard after a configurable number of seconds. This is separate from ***Paste Once*** because it is a time-based safety net, not a read-count one.

#### How to configure <a href="#how-to-configure" id="how-to-configure"></a>

1. Go to ***File*** – ***Settings*** – ***Application*** – ***Clipboard*** – ***Advanced***.
2. Enable ***Clear clipboard after*** and set the delay in seconds.
3. Click ***OK***.

#### Symptoms that point to this setting <a href="#symptoms-that-point-to-this-setting" id="symptoms-that-point-to-this-setting"></a>

* The clipboard is full right after you copy, but empties on its own a few seconds later.
* The profiler shows a `Clear` line some seconds after the copy, without any `Render - Requester : 0` or blocklist activity.

#### Recommended values <a href="#recommended-values" id="recommended-values"></a>

* **10–30 seconds**: balanced, long enough for most paste workflows, short enough to limit exposure.
* ***Disabled***: only if you use ***Paste Once*** or rely on an external clipboard manager for cleanup.

### Blocklist management <a href="#blocklist-management" id="blocklist-management"></a>

The ***Status*** tab of the clipboard diagnostic window lists every process that has requested the clipboard since Remote Desktop Manager started. Each entry shows the process name, PID, command line, and whether the process is currently allowlisted, blocklisted, or detected as an auto-reader.

#### Add a process to the blocklist <a href="#add-a-process-to-the-blocklist" id="add-a-process-to-the-blocklist"></a>

1. Open the ***Clipboard diagnostic*** window from the ***Help*** menu.
2. In the ***Status*** tab, right-click the process you want to block.
3. Select ***Add to blocklist***.

Blocklisted processes receive an empty clipboard when they request credentials from Remote Desktop Manager.

#### Add a process to the allowlist <a href="#add-a-process-to-the-allowlist" id="add-a-process-to-the-allowlist"></a>

Use the allowlist for trusted applications that Remote Desktop Manager would otherwise block for example, because they trigger the [null requester check](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#null-requester-check) or were flagged as auto-readers.

1. Open the ***Clipboard diagnostic*** window from the ***Help*** menu in the ribbon of Remote Desktop Manager.
2. In the ***Status*** tab, right-click the process you want to allow.
3. Select ***Add to allowlist***.

#### Remove a process from either list <a href="#remove-a-process-from-either-list" id="remove-a-process-from-either-list"></a>

1. In the ***Status*** tab, right-click the process.
2. Select ***Remove from blocklist*** or ***Remove from allowlist***.

### Browser and application compatibility <a href="#browser-and-application-compatibility" id="browser-and-application-compatibility"></a>

Some applications request the clipboard in a way that triggers the [null requester check](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#null-requester-check). The list below is maintained as issues are reported. If the application you use is not listed, follow the [Test in 30 seconds](https://docs.devolutions.net/rdm/kb/troubleshooting-articles/clipboard-diagnostic/#test-in-30-seconds) flow to determine whether the null requester check is involved.

| Application         | Versions affected    | Status                        | Notes                                                                |
| ------------------- | -------------------- | ----------------------------- | -------------------------------------------------------------------- |
| **Google Chrome**   | To be verified       | Triggers null requester check | Workaround: disable the null requester check, or use Microsoft Edge. |
| **Microsoft Edge**  | All current versions | Works                         | Requests the clipboard with a visible window handle.                 |
| **Mozilla Firefox** | To be verified       | To be verified                |                                                                      |
| **Brave**           | To be verified       | To be verified                | Chromium-based, likely to match Chrome behaviour.                    |

### Send a diagnostic report to support <a href="#send-a-diagnostic-report-to-support" id="send-a-diagnostic-report-to-support"></a>

If none of the above resolves the issue, send a diagnostic report so the support team can review the profiler output:

1. Open the ***Clipboard diagnostic*** window from the ***Help*** menu in the ribbon of Remote Desktop Manager.
2. Reproduce the failing copy and paste so the profiler captures the event.
3. Click ***Send***.
4. In the ***Send message to Devolutions support team*** window, include a short description of:
   * The source entry type (credential, web browser, etc.).
   * The target application and version (for example, Chrome 135).
   * Whether the same copy works in another application.
5. Click ***Send***.

### See also

* [Devolutions Academy - How to perform a clipboard diagnostic](https://academy.devolutions.net/student/page/2397682-how-to-use-the-clipboard-diagnostic)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.devolutions.net/rdm/knowledge-base/troubleshooting-articles/clipboard-diagnostic.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.