Managing contactSync Contact Folders: Renaming, Duplicates and Missing Folders

Purpose

Questions about the folder contactSync writes into come up constantly, especially during or after a mailbox migration: an old folder and a new one both exist, duplicates appear, or the folder vanishes from Outlook entirely. This article covers the folder options that matter, and the one that can lose users' own data if chosen carelessly.

Choose the folder behaviour deliberately

The options controlling how contactSync treats contacts in the target folder differ enormously in risk, and the manual attaches explicit warnings to two of them.

Synchronize into a dedicated subfolder. The safest arrangement and the usual recommendation: contactSync writes into its own named folder beneath the mailbox's Contacts folder, and users' personal contacts in the root folder are untouched.

Allow synchronization into the well-known Contacts folder. This lets contactSync write into the mailbox's standard Contacts folder. The manual's warning is direct: it "allows you to directly change and delete contacts that your employees have created", and may confuse people. Choose it only with a clear reason.

Within that, three options govern what happens to contacts contactSync did not create:

• Do not touch untagged contacts — existing contacts remain untouched unless contactSync created them. contactSync will not create a contact where a non-contactSync one already exists.
• Synchronize an additional contact for each untagged contact — contactSync creates its own parallel contact alongside the existing one. This is the manual's recommendation where synchronization into the well-known folder is needed.
• Synchronize untagged contacts with contactSync — prefaced in the manual with "Please exercise extreme care with this option." All existing contacts are synchronized even if contactSync did not create them, which means contacts your employees created below the selected folder can be synchronized and possibly deleted, causing them to lose information.

If you are troubleshooting unexplained contact loss in mailboxes, check which of these three is set before anything else.

Renaming or replacing a folder

A folder often ends up renamed during a migration — a space becoming an underscore, or a rebrand — leaving both old and new in every mailbox.

1. Confirm no policy still targets the old folder. Check every policy, including test policies, not just the one you have in mind.
2. Remove the old folder using the policy option Delete selected contact folder in the mailboxes during the next execution, which is the supported way to have contactSync clear up after itself.
3. Point the policy at the folder name you want on the Contact Folder tab.
4. Run the policy against a small set of mailboxes first and confirm the result before applying it broadly.

Bulk folder manipulation with Remove-MailboxFolder and New-MailboxFolder is possible, but it operates outside contactSync's knowledge of what it created. Prefer the policy option where one exists, and treat scripted folder removal as a last resort run against a pilot group first.

Duplicates

Duplicate contacts and duplicate folders have several causes, and they are worth distinguishing before acting.

Historical folder names. Where policies have targeted different folder names over time, each leaves its own set behind. The older sets are no longer managed by any policy and will never update — they simply persist.

Multiple policies writing into one folder. Each policy treats the folder's contents as its own to reconcile, so they delete each other's contacts in turn. Give every policy its own dedicated folder.

Client-side merging. This one misleads people badly. Mobile contact apps commonly merge cards across folders by display name, so a user can see one contact that combines a current synchronized entry with a stale legacy one. The server-side data is correct; the merged view is not. Always check folder contents on the server rather than on the phone.

A quick diagnostic: compare item counts between a recently created mailbox and an affected one. A new mailbox typically shows zero items in the root Contacts folder and the full set in the subfolder. A long-standing mailbox showing a large number of items in the root folder is carrying an unmanaged legacy set.

Hybrid: mailboxes on both sides

Mailboxes in Exchange on-premises and in Exchange Online can be selected within the same policy and can synchronize into the same folder name — provided no Recipient Type has been selected on the Mailboxes tab. A Recipient Type selection prevents mixing the two.

This matters during a migration, when mailboxes move between the two over time. Selecting recipients by group rather than by recipient type means a mailbox that moves keeps receiving contacts without the policy needing to be edited.

The folder has disappeared from Outlook

Before investigating contactSync: the contact folder and its subfolders are not visible in the new Outlook. If a user reports the folder missing, check which Outlook they are running before anything else — there is a button in the top right of the app to switch between the two versions.

Classic Outlook displays the folders normally. If classic Outlook is not available on the machine, Microsoft documents how to reinstall it.

This costs nothing to check and explains a large share of "the contacts have vanished" reports.

Before deleting anything

Two cautions worth accepting deliberately:

• Confirm the folder is one contactSync owns. If users' personal contacts are in the same folder, deleting it takes their data with it. This is the real risk in the Synchronize untagged contacts option above.
• Confirm the policy is healthy before clearing a folder that you expect it to repopulate. If the policy is failing for an unrelated reason, the contacts will not come back on the next run.

References

• contactSync 8.7 Manual p.163 — Allow synchronization into the well-known contact folder; Do not touch untagged contacts; Synchronize untagged contacts with contactSync; Synchronize an additional contact for each untagged contact, with the manual's warnings.
• contactSync 8.7 Manual p.113 — the Mailboxes tab; hybrid selection permitted when no Recipient Type is selected.
• contactSync 8.7 Manual p.264 — Contact Folder is not visible in Outlook / Outlook Web Access; the new Outlook and switching back to classic.
• The current contactSync manual is published by NETsec at netsec.de.