Specific settings Outlook Add-in

All registry values (required and optional) that the FileCap Outlook add-in reads are described on this page.

HKEY_CURRENT_USER or HKEY_LOCAL_MACHINE#

Most registry values described on this page can be placed in HKEY_CURRENT_USER and/or HKEY_LOCAL_MACHINE. The exceptions are marked in the tables.

Settings placed in HKEY_LOCAL_MACHINE will be used for all users logged in on the system.
Settings placed in HKEY_CURRENT_USER only apply to a specific user. These values override the HKEY_LOCAL_MACHINE values.

When Outlook starts, the add-in reads these keys in this order. A value read later overrides the same value read earlier:

HKEY_LOCAL_MACHINE\SOFTWARE\FileCap
HKEY_CURRENT_USER\Software\FileCap
HKEY_CURRENT_USER\Software\FileCap\Users

Changes are read when Outlook starts, so restart Outlook after changing a value.

Default registry locations#

By default, all registry values are written to:

HKEY_LOCAL_MACHINE\SOFTWARE\FileCap or HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\FileCap depending on whether a 64- or 32-bit version of Outlook is installed (32-bit Outlook on 64-bit Windows uses WOW6432Node).

The HKEY_CURRENT_USER location is:

HKEY_CURRENT_USER\Software\FileCap

The installer also writes to HKEY_CURRENT_USER#

The installer writes Server, APIKey, Language, DebugMode and APPDIR to HKEY_LOCAL_MACHINE and to HKEY_CURRENT_USER of the account that runs the installer. The add-in itself also writes Language and DebugMode to HKEY_CURRENT_USER when a user changes the language or the log level in the FileCap panel.

Because HKEY_CURRENT_USER overrides HKEY_LOCAL_MACHINE, a change you make in HKEY_LOCAL_MACHINE (for example with a Group Policy) has no effect for a user who still has the same value in HKEY_CURRENT_USER. After changing a value in HKEY_LOCAL_MACHINE, also check HKEY_CURRENT_USER\Software\FileCap for that user, and update or delete the value there.

Value types#

Text values are REG_SZ.
On/off values are REG_SZ with true or false (not case sensitive). A REG_DWORD 1 is not read as true. Any value other than true counts as false.
Numeric values (DebugMode, StartupConnectionRetryCount, AttachmentSizeThreshold) can be REG_SZ or REG_DWORD.

Required registry values per installation#

API settings#

An API key is required to communicate with the FileCap server. By default, the installation will place it in HKEY_LOCAL_MACHINE (and in HKEY_CURRENT_USER of the installing account, see above).

Name	Type	Value
APIKey	REG_SZ	XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Server	REG_SZ	yourcompany.filecap.eu

Server is the hostname of your FileCap environment. From version 2026.10.0 the add-in removes https://, a trailing slash and surrounding spaces itself. The add-in always connects over https.

Optional registry values#

The following registry values are optional.

Language#

This optional registry value makes it possible to display the FileCap Outlook add-in in a specific language. The installer writes the language chosen during installation (default system). If the value is missing, the add-in uses English. With system, the add-in uses the language of the Windows regional settings. If that language is not supported, it falls back to English.

Users can also change the language in the FileCap panel. This writes Language to HKEY_CURRENT_USER.

The following options are currently supported:

Language	Type	Value
System language	REG_SZ	system
Dutch	REG_SZ	nl
English	REG_SZ	en
Swedish	REG_SZ	sv
Finnish	REG_SZ	fi
Norwegian	REG_SZ	no
Danish	REG_SZ	da
German	REG_SZ	de

Log level#

DebugMode sets how much the add-in writes to the Windows event log. The installer writes 0. The log level dropdown in the FileCap panel writes this value to HKEY_CURRENT_USER. See Troubleshooting for where to find the log.

Name	Type	Value	Description
DebugMode	REG_SZ or REG_DWORD	0	Errors only. Note This is the default value.
DebugMode	REG_SZ or REG_DWORD	1	Errors and information.
DebugMode	REG_SZ or REG_DWORD	2	Everything, including debug details. Use this when you report a problem.

Sending when the FileCap server is unreachable#

If this registry value is used, it becomes possible to send emails even when the FileCap server is unreachable.

Warning: This option can cause data leaks to occur.

Name	Type	Value	Description
AllowFailedConnection	REG_SZ	false	Sending email is not possible when the FileCap server is unreachable. Note This is the default value if this registry value is not set.
AllowFailedConnection	REG_SZ	true	Sending email is possible even when the FileCap server is unreachable. The user is asked whether to send the message without FileCap.

Retrying the connection at start-up#

Name	Type	Value	Description
StartupConnectionRetryCount	REG_SZ or REG_DWORD	0 to 65535	How many extra times the add-in tries to load its settings from the FileCap server when Outlook starts, with 2 seconds between attempts. Useful when the network is not ready yet when Outlook starts. Default `0` (no retries).

Using FileCap for attachments and messages#

These values force or preset the use of FileCap on the PC. They add to the portal setting Use FileCap for all attachments on the Add-ins page. They cannot switch that portal setting off. With any of these values set to true, attachments in meeting requests are blocked, because FileCap cannot send them.

Name	Type	Value	Description
ForceUseFileCapForAttachments	REG_SZ	true / false	`true`: every message with attachments is sent with FileCap. Default `false`.
SetDefaultUseFileCapForAttachments	REG_SZ	true / false	`true`: FileCap is switched on by default for every new message. The user can still switch it off. Default `false`.
ForceUseFileCapForMessageAndAttachments	REG_SZ	true / false	`true`: every message is sent with FileCap, message text and attachments, also without attachments. Default `false`.

Large attachments added with Attach File#

Name	Type	Value	Description
AttachmentSizeThreshold	REG_SZ or REG_DWORD	Size in MB	A file larger than this, added with Outlook’s Attach File button, is not copied into the message. The add-in adds an empty placeholder and sends the file from its original location with FileCap. Default: not set (off). The older spelling `AttachmentSizeTreshold` is also read.

This value is separate from the portal setting Automatically send with FileCap when attachment size exceeds (MB), which is set on the Add-ins page and cannot be set in the registry.

Restoring the original message after sending#

The add-in can put the original message, with its attachments, in Sent Items after sending, instead of the FileCap version. The same settings exist on the Add-ins page of the portal.

Name	Type	Value	Description
RestoreOriginalMail	REG_SZ	true / false	`true`: restore the original message. This only switches restoring on: when the portal setting Restore original mail item after sending is on, `false` does not switch it off. Default `false`.
RestoreUseSeparateFolder	REG_SZ	true / false	`true`: put restored messages in a separate folder. When set, this overrides the portal setting Create folder for restored items. Default: the portal setting.
RestoreFolderInsideSentItems	REG_SZ	true / false	`true`: create that folder inside Sent Items. `false`: create it next to Sent Items. When set, this overrides the portal setting Put restore folder inside sent items. Default: the portal setting.
RestoreFolderName	REG_SZ	Folder name	Name of the folder for restored messages. When set, this overrides the portal setting Restore folder name. Default: the portal setting, or `FileCap` if that is empty.

Excluding senders#

Name	Type	Value	Description
ExcludeFromFileCap	REG_MULTI_SZ	One email address or domain per line	Messages from these senders are sent as regular email, without FileCap. A line that is not a full email address is treated as a domain, for example `example.com`. Business rules set in the portal still apply. Only read from HKEY_LOCAL_MACHINE. The type must be REG_MULTI_SZ.

“Do not show again” choices#

When a user ticks the option not to show a FileCap warning again, the add-in stores that choice in HKEY_CURRENT_USER\Software\FileCap as REG_SZ True. Delete the value to show the warning again.

Name	Warning
DoNotShowLinkDialogAgain	Confirmation before generating a link. This value can also be set to `true` in HKEY_LOCAL_MACHINE to skip the confirmation for all users.
DoNotShowAddRecipientDialogAgain	Recipients added after a link was generated.
DoNotShowMissingGeneratedLinkDialogAgain	The generated link is missing from the message text.
DoNotShowSavedMessageDialogAgain	The message was saved in Drafts.
DoNotShowDraftWarningDialogAgain	Attachments that must be added again before sending from Drafts.
DoNotShow0kbMessageDialogAgain	Attachments that must be added again before sending from Drafts (second variant of the warning above).

Apart from DoNotShowLinkDialogAgain, these values are only read from HKEY_CURRENT_USER.

Values written by the add-in or the installer#

Do not create or change these values yourself.

Name	Location	Description
APPDIR	HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER	The installation folder, written by the installer.
OutlookUserAPIKey…	HKEY_CURRENT_USER\Software\FileCap\Users	One value per registered sender, written when the user registers the add-in. Delete the value for a sender to register again.