Troubleshooting: Outlook Add-in

Solutions for common Draftable Clean Outlook add-in issues — deployment, manifest validation, cleaning failures, updates, cache clearing, and removal.

This guide covers common issues when deploying and using the Draftable Clean Outlook add-in. For installation steps, see Installing Draftable Clean Outlook Add-in. For cleaning behavior (password-protected files, unsupported formats, tracked changes), see Troubleshooting: Cleaning issues.

For this public release, use the supported pairing of Draftable Clean desktop 26.11.0 and Outlook add-in 1.13.0.0. If you see a version mismatch, update both products. If your organization manages Draftable Clean or the add-in for you, ask your administrator to update them.

Add-in not appearing for users?

• Wait up to 72 hours for deployment to fully propagate
• Verify users are in the correct security group (if using group-based deployment)
• Have users restart their Outlook application and machine
• Check that users have active Microsoft 365 subscriptions with Office apps
• Ensure users are signed in with their organizational account
• Verify the Draftable Clean desktop application is installed on the user’s machine

Manifest validation failed?

• Copy the manifest URL exactly as shown in Installing Draftable Clean Outlook Add-in, including https://
• Verify the manifest URL is accessible from your network (not blocked by firewall or proxy)
• Check that dl.draftable.com is not blocked by your organization’s web filter
• Try accessing the URL directly in a browser to confirm it is reachable

Add-in opens but does not clean files?

• Ensure the Draftable Clean desktop application is installed and licensed on the user’s machine
• The desktop application must be running for the add-in to function — it will attempt to launch it silently, but this may fail if the application is not installed
• Check that the desktop application version is compatible with the add-in version
• Verify that localhost network calls are not being blocked by corporate security tools, firewalls, or endpoint protection software — the add-in communicates with the desktop application via localhost
• In Classic Outlook, the Draftable Clean pane must be open for attachments to be cleaned. Pin the pane using the 📌 icon so it opens when you compose a message. See Does Classic Outlook ask you to open the pane before sending? below
• If the add-in loses its connection to Draftable Clean on a shared or multi-user machine, cannot connect from Outlook on the web or New Outlook, or Draftable Clean hangs when you close it, update Draftable Clean to 26.11.0, which fixes these connection problems

Send-time verification isn't enabled for this account, or the send-time check is off?

The add-in installs, opens and cleans attachments normally, but the send-time check, which confirms the cleaned files are the ones being sent, is not running. In New Outlook and Outlook on the web, users are asked to confirm every send that has cleaned attachments, with the message:

Send-time verification isn’t enabled for this account, so Draftable Clean can’t confirm this email’s attachments before it’s sent.

Classic Outlook never runs this check, so Classic users do not see this message.

• Confirm it: in Outlook on the web or New Outlook for Windows, add an attachment to an email and let it clean, then close and reopen the Draftable Clean pane. Hover over the version line at the bottom of the pane. Graph ok means the check is running. Graph off followed by a reason in brackets means it is not (Graph off (token) usually means the permissions are missing)
• Most likely cause if this started after the add-in updated to 1.12.114.0: your organization had approved the earlier app, and that approval does not carry over. From 1.12.114.0 the add-in connects through Draftable’s app Draftable Clean, so an administrator needs to approve Draftable Clean once. See Approving Draftable Clean in Microsoft Entra. You do not need to remove or redeploy the add-in
• Next most likely: Draftable Clean was never approved. Deploying the add-in does not approve it, so an administrator approves it separately with the approval link. You do not need to redeploy the add-in
• Also possible: an approval was started but not completed. The approval link reports Consent was not granted or Consent was not completed, with the reason Microsoft gave. An administrator can use the approval link again at any time
• Users must be signed in to Outlook with the organizational account the add-in was deployed to. A personal Microsoft account cannot receive your organization’s permissions
• If none of these apply, export your diagnostic logs and contact support, including the full text of the version line
• The send-time check is not used in Classic Outlook, where the version line shows Server check: not available in Classic once Draftable Clean is approved, or Graph off (token) before approval. This is expected. Cleaning and Send Protection work as normal in Classic Outlook

Does Classic Outlook ask you to open the pane before sending?

When you send an email from Classic Outlook without the Draftable Clean pane open, you may see this message:

Draftable Clean needs its add-in pane open to apply your organisation’s send settings. Click Review to open it, then send again.

What to do: click Review to open the Draftable Clean pane, let your attachments finish cleaning, then send again. Click Don’t Send to return to the email without sending.

Why it happens: in Classic Outlook, attachments are cleaned in the Draftable Clean pane, so the pane must be open. If the pane has not been opened for the email, Draftable Clean cannot read your organisation’s send settings and asks you to open it before the email goes. The configured Allow, Prompt, or Block send-protection action is still respected when the pane is closed.

Stop it happening: pin the pane. Open the Draftable Clean pane while composing an email and click the pin icon at the top of the pane. Outlook then opens the pane automatically every time you compose an email, so attachments are cleaned as you add them.

Can an administrator open or pin the pane for everyone? No. Microsoft does not allow Outlook add-ins built on its current add-in platform to open their own pane, and Microsoft 365 has no setting to pin an add-in pane on users’ behalf. Each user pins the pane once in their own Outlook. This is a limitation of Classic Outlook, not a setting in Draftable Clean.

If screen space is tight: New Outlook for Windows and Outlook on the web clean attachments in the background without the pane open, so users there do not need to pin it.

Does "Open Draftable Clean to check attachments before sending" appear in Classic Outlook?

In Classic Outlook, when the Draftable Clean pane is closed and the email has recipients, a banner appears on the email:

Open Draftable Clean to check attachments before sending.

What to do: open the pane with Manage Attachments in the ribbon. The attachments are then cleaned, or shown as Skipped, for your recipients.

It can appear even when your recipients do not need cleaning. With the pane closed, Classic Outlook cannot ask Draftable Clean which cleaning rule applies, so it shows the banner to be safe, including after you add a recipient whose rules skip cleaning. This is expected. Open the pane and the attachments show Skipped. To avoid the banner, pin the pane so it opens every time you compose an email.

Does an attachment show "File exceeds maximum size (24 MB)", and is sending held?

The add-in can clean attachments up to about 24 MB, which is Microsoft’s limit for a file an Outlook add-in can attach. A larger attachment that needs cleaning shows Failed with this message, and sending is held because the attachment still needs cleaning. This is Microsoft’s limit, not a fault in Draftable Clean.

To send the file:

• Share it through your DMS or a link instead of attaching it
• Or, if the email is going to a recipient whose rules do not require cleaning (Skip Cleaning), the attachment is sent as it is, whatever its size

Are the Save to DMS buttons missing?

The add-in shows Save to iManage, Save to NetDocuments, Save to SharePoint or Save to Epona 365 on cleaned attachments and attachments converted to PDF. If a button is missing:

• Check that the DMS is turned on in the Draftable Clean desktop application under Settings > Integrations. The add-in shows a button only for each DMS turned on there
• Check that the attachment shows Cleaned. Skipped files and files still being cleaned have no Save buttons
• Update Draftable Clean to the latest version. Older versions of Draftable Clean do not offer saving from the add-in

See Saving cleaned attachments to your DMS. For problems connecting to the DMS itself, see Troubleshooting: DMS integrations.

Is a Microsoft Purview protected attachment not supported, or sent still protected?

A protected attachment shows Protected with the message:

Protected by Microsoft Purview: not supported. The attachment will be sent as it is, still protected.

• Support is turned off: cleaning protected files is off by default, and an administrator turns it on by policy. Until then, protected attachments are sent as they are, still protected
• Draftable Clean is older than 26.11.0: the add-in cleans protected attachments only with Draftable Clean 26.11.0 or later
• You do not have the right to extract content from the file: Draftable Clean can clean a protected file only if your Microsoft 365 account has the Extract right for it. Ask the file’s owner or your administrator
• Your administrator blocks unprotected copies: if policy blocks saving protected files as unprotected copies, protected attachments are not cleaned and stay protected
• Skip Cleaning applies to your recipients: protected attachments are sent as they are, still protected. This is expected

See Cleaning files protected by Microsoft Purview.

Does "This site is trying to open Draftable Clean" appear in the pane?

When the Draftable Clean desktop application is not running, the add-in pane starts it for you. Outlook shows the pane using Microsoft’s WebView2 component, which asks for confirmation before it opens a desktop application:

This site is trying to open Draftable Clean. https://dl.draftable.com wants to open this application.

This is standard Microsoft security behaviour, not a fault in Draftable Clean.

For one user: tick Always allow dl.draftable.com to open links of this type in the associated app, then click Open. The prompt does not appear again for that user, unless the add-in cache is cleared, which resets the choice.

For everyone: administrators can pre-approve the launch for all users on a machine with this WebView2 setting, deployed through Group Policy, Microsoft Intune or another management tool:

Key: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge\WebView2
Value name: AutoLaunchProtocolsFromOrigins
Value type: REG_SZ
Value data: [{"allowed_origins":["https://dl.draftable.com"],"protocol":"draftableclean"}]

Test on one machine before rolling out. Microsoft documents AutoLaunchProtocolsFromOrigins as a Microsoft Edge policy and has not formally listed it for WebView2. A small number of customers have confirmed that it works at this location, but it may not work in every environment. If the prompt still appears after you apply it, contact [e-mail]. The value is read as JSON: copy it exactly, including the double quotes and square brackets, or the setting is silently ignored. Restart Outlook after applying it.

This setting belongs to Microsoft’s WebView2 component, not to Draftable Clean, and only suppresses the prompt. It does not install or start Draftable Clean. If nothing happens when the pane tries to start the application, check that Draftable Clean is installed on the machine.

Is Draftable Clean off in New Outlook?

• In the Draftable Clean desktop application, open Settings > Add-In
• Turn on Clean attachments in New Outlook
• When this switch is off, attachments sent from New Outlook are not cleaned and Draftable Clean does not run pre-send checks
• This switch affects New Outlook for Windows only. Classic Outlook and Outlook on the web are unaffected by the switch. New Outlook support remains in beta
• If the switch is disabled or locked, your administrator controls it through policy. Contact your administrator if you need it changed
• After changing the switch, click Check again in the add-in pane or open a new message

Why was an attachment not cleaned?

• Digitally signed PDFs are intentionally refused because changing a signed file would invalidate its signature
• ZIP archives and embedded emails can contain items that Draftable Clean cannot check. The Unsupported attachment types send-protection setting controls whether those items are allowed, prompt the sender, or block sending

Does Outlook report a mailbox size limit?

• If Outlook refuses the cleaned copy because the email is near or over its mailbox size limit, remove some attachments and try again, or send the file separately. The original remains attached when Outlook refuses the cleaned copy
• This error does not require additional Microsoft 365 consent. For on-premises or hybrid mailboxes, the add-in keeps its existing Outlook fallback when the mailbox-size lookup is unavailable

Are both the original and cleaned copies attached?

• Open Review Attachments and wait for the cleaned replacement to finish
• Check that the add-in is 1.12.110.0 or later, which fixes duplicate copies, recipient changes, and reattached files. If it is older, ask your administrator to update it
• If an unwanted copy remains, use Delete duplicate when the pane offers it. Do not rely on the filename alone to identify which copy is clean. If the problem persists, keep the email unsent and contact support with diagnostic logs

Need to update to a new version?

• If your organisation deployed the latest manifest URL, updates within the same major version arrive automatically. For a pinned deployment, use the current pinned manifest URL in Installing Draftable Clean Outlook Add-in
• Return to Integrated apps in the Admin Center
• Find the existing Draftable Clean add-in in the list and click on it
• Look for an Update option and provide the new manifest URL
• The updated version will roll out to users automatically
• Users may need to restart Outlook to see the update

Need to clear a cached version of the add-in?

• In the Draftable Clean desktop application, go to Settings > Troubleshooting
• Click Clear add-in cache
• Restart Outlook for the change to take effect

See Troubleshooting: Diagnostic logs and support for more detail.

Remove or uninstall the add-in?

Uninstalling the Draftable Clean desktop application does not remove the Outlook add-in. The add-in stays in Outlook and keeps trying to reach the desktop application, which can stop users sending emails with attachments. Remove the add-in first, and uninstall the desktop application only once the add-in has gone from users’ Outlook.

• Go to Integrated apps in the Admin Center
• Click on the Draftable Clean add-in
• Select Remove or Delete
• Confirm the removal
• The add-in will be removed from users’ Outlook within 72 hours

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Need help?

If you experience issues not covered above, export your diagnostic logs and contact the Draftable team at [e-mail].