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This page is about installing EndNote’s Cite While You Write add-in — the Clarivate reference manager’s toolbar in Microsoft Word — and not about Word’s own built-in endnote feature. If what you actually want is the note that appears at the end of a document, that is in Word itself: References ▸ Insert Endnote (Alt+Ctrl+D on Windows), it needs no software installed, and Microsoft documents it at Insert footnotes and endnotes. Two unrelated things share the word. Nothing below will help with the Word feature.
Version, platform and date. This describes EndNote 2025 (Clarivate’s current desktop release) on Windows and macOS, checked in August 2026 against Clarivate’s own EndNote 2025 documentation — which maintains separate Windows and macOS trees, because the repair paths are genuinely different programs, not the same dialog with different keys. EndNote 21 behaves the same way for everything on this page. Where a step differs by platform it is stated per platform; a guide that blurs the two is useless at exactly the moment you need it.
This page is installation and repair only. For actually using EndNote once the tab appears — building the library, importing references, inserting citations, switching output style, stripping field codes for submission — see the EndNote first-project walkthrough.
The happy path is three clicks, and it is not where anyone gets stuck
Cite While You Write (CWYW) is not a separate download. There is no plugin to fetch, no add-in store entry, no licence key of its own. It is a component of the EndNote Desktop installer, selected by default. Install EndNote with Word closed, reopen Word, and an EndNote 2025 tab is on the ribbon. Clarivate’s own success criterion is exactly that: “When word processor support is correctly installed, you will see an EndNote 2025 tab in Word.”
So the whole of the install procedure is:
- Quit Word — and on macOS, quit every Office application. This is not a formality; see the next section.
- Run the EndNote installer, accepting the default component selection (which includes Cite While You Write).
- Open Word. The EndNote 2025 tab is there.
That is all the happy path deserves. What follows is the part that is spread across four separate Clarivate pages in two documentation trees, and that university IT desks field over and over.
The install-order rule — the single most common cause
If you install or upgrade Microsoft Word after EndNote, Cite While You Write breaks. Clarivate names this outright as a cause of CWYW installation problems on macOS, and the same dependency holds on Windows: the add-in is written into the Word installation that existed at the time EndNote ran, so a later Word install, a version upgrade, or a Microsoft 365 channel change can leave EndNote installed, licensed and working — with no tab in Word.
This matters most in two ordinary situations:
- A new machine build. IT images EndNote from the site licence, then Office lands afterwards from a different deployment. EndNote looks fine. The tab never appears.
- An Office upgrade mid-project. The tab was there last month and is gone this month, and nothing about EndNote changed.
The fix is not to uninstall and reinstall EndNote from scratch, and it is not to reinstall Word. It is to re-run EndNote’s own word-processor-support installation — which is a different procedure on each platform, and is the subject of the next two sections. Try that before anything more drastic.
Windows: the repair ladder, in this order
Windows has no EndNote Customizer. The Windows repair is a three-rung ladder, and the rungs are worth trying in order because each is more disruptive than the last.
Rung 1 — Re-enable the COM add-in
Word can switch a COM add-in off — after a crash, an unclean shutdown, a Word update, or a user unticking it once and forgetting. EndNote is still installed; Word simply is not loading it. In Word:
File ▸ Options ▸ Add-ins, set Manage to COM Add-ins, click Go, tick EndNote Cite While You Write, click OK, then quit and reopen Word.
This costs thirty seconds and resolves a large share of missing-tab reports. Do it first.
Rung 2 — Check Disabled Items
This is the rung almost everyone skips, and it is the reason rung 1 sometimes appears not to work. When Word decides an add-in caused a crash, it does not merely untick it — it moves it to a separate Disabled Items list, where it will not appear in the COM Add-ins dialog at all. If you looked for “EndNote Cite While You Write” in rung 1 and it was not listed, this is why.
Clarivate’s instruction for Word 2010, 2013, 2016, 2019 and Office 365: select Options from the File menu, select Add-ins, set Manage to Disabled Items, and click Go. Select the EndNote entry, enable it, then restart Word and repeat rung 1 if the tab is still absent.
Absent from COM Add-ins and absent from Disabled Items means the component genuinely is not installed on this machine. That is rung 3.
Rung 3 — Repair or Modify the EndNote installation
Clarivate is explicit about the precondition, and it is the step people get wrong: “Before you attempt to Repair or Modify your EndNote installation in order to use Cite While You Write, you must make sure that your word processor is not running.” Not minimised — not running. A Word process still alive in the background is enough to make the repair silently fail to write the add-in, after which the tab is still missing and the repair looks broken.
With Word fully closed, either run the EndNote installer again and choose Repair or Modify, or reach the same options through Windows Apps & features. In the component list, set Cite While You Write for Microsoft Office to Will be installed on local hard drive. Complete the installation, then open Word.
You will generally need local administrator rights for rung 3. On a managed institutional machine that is the point at which this becomes a ticket rather than a self-service fix — which is a good reason to have genuinely exhausted rungs 1 and 2 first.
macOS: the Customizer, and where it actually lives
On macOS none of the above exists. Word for Mac has no COM Add-ins dialog and no Disabled Items list, so every Windows instruction you find is inapplicable. The Mac tool is the Customizer, and the single most common reason people cannot find it is that it is not in Word.
The Customizer is launched from EndNote’s own application menu: start EndNote, then from the EndNote 2025 menu select Customizer. It installs, reinstalls or removes individual EndNote components after the main program is already installed — which is exactly the operation needed when Word arrived after EndNote.
Clarivate’s steps, in order:
- “Make sure no applications are running—including virus protection software and any Microsoft Office applications.” Anti-virus is named in the documentation, not added here; a scanner holding the Word startup folder open is a real failure mode on macOS.
- Start EndNote.
- From the EndNote 2025 menu, select Customizer.
- On the Component Selection dialog, select the components to install or keep installed and click Next. These must include Cite While You Write.
- Complete the installation, then open Word and confirm the EndNote 2025 tab.
The macOS manual fallback
If the Customizer completes but the tab still does not appear, Clarivate documents placing the add-in by hand. Find Word’s startup folder through Word’s Preferences ▸ File Locations. Then open the Cite While You Write folder inside the EndNote 2025 application folder (under Applications), copy the bundle file — EndNote CWYW Word 16.bundle — and paste it into Word’s startup folder.
Clarivate’s own emphasis on the precondition is worth repeating verbatim: “Quit Word. This step is important!” Copying the bundle into the startup folder while Word is running will not produce a working tab, and may leave a partially written file behind.
What looks like a broken install but is a version or platform limit
A repair cannot fix a capability that does not exist in your configuration. Before running any of the above, rule these out — reinstalling will not change any of them.
- Word version. CWYW requires Word 2016, 2019, 2021 or Microsoft 365. Older Word will not take the add-in.
- Word Online. Browser-based Word does not use the desktop add-in at all. CWYW there runs through EndNote Web and is available to EndNote 2025 and EndNote 21 users only. On an older desktop version this is a licensing and version limit, not a fault to repair.
- Google Docs. Same position as Word Online — via EndNote Web, EndNote 2025 and 21 only. If you need a manager with a mature Google Docs path, Zotero’s Google Docs integration is the closer comparison.
- macOS Word only. On macOS, CWYW works with the locally installed desktop Word; it is also compatible with Apple Pages.
- Linux. There is no native EndNote Desktop client for Linux, therefore no Word add-in. EndNote Web in a browser is the only route.
- Old EndNote on a new macOS. EndNote 20 and earlier were not designed for macOS Tahoe. Clarivate’s advice there is to upgrade to EndNote 2025, not to repair.
Symptom to fix, at a glance
| Symptom | Platform | What to do |
|---|---|---|
| No EndNote tab; EndNote itself runs fine | Windows | Rung 1: File ▸ Options ▸ Add-ins ▸ Manage: COM Add-ins ▸ Go ▸ tick EndNote Cite While You Write. |
| EndNote is not listed in the COM Add-ins dialog | Windows | Rung 2: Manage: Disabled Items ▸ Go. Word moved it there after a crash. |
| Not in COM Add-ins and not in Disabled Items | Windows | Rung 3: close Word entirely, Repair/Modify EndNote, set Cite While You Write for Microsoft Office to “Will be installed on local hard drive”. |
| No EndNote tab; Word was installed or upgraded after EndNote | macOS | EndNote 2025 menu ▸ Customizer ▸ Component Selection ▸ include Cite While You Write ▸ Next. Quit all Office apps first. |
| Customizer completed, still no tab | macOS | Quit Word, then copy EndNote CWYW Word 16.bundle from the EndNote 2025 Cite While You Write folder into Word’s startup folder (Preferences ▸ File Locations). |
| Tab appears, then vanishes after a Word crash | Windows | Disabled Items, then COM Add-ins. Recurrence usually means an unstable third-party add-in, not EndNote. |
| Tab appears but citations will not insert | Both | Not an install fault — this is a library or document state issue. See the usage walkthrough. |
| No CWYW in Word Online or Google Docs | Both | Version gate. EndNote Web CWYW is EndNote 2025 and 21 only; nothing to repair. |
| Repair runs but changes nothing | Windows | Word was still running. Close every Word window and confirm no background Word process, then repair again. |
Deploying this across a group or a department
Three things save the most support time when more than one person is involved. First, fix the order in the build: Office first, EndNote second. Reversing it guarantees a wave of missing-tab tickets that each need the Customizer or a Repair. Second, expect a repeat after any Office upgrade and schedule the CWYW reinstall alongside it rather than waiting for reports. Third, decide the library and licence arrangement before anyone installs anything — shared libraries, ownership and licence scope have consequences that are far easier to get right at the start than to unpick later; see citation management software for a research group.
If EndNote is not settled yet, the install question is premature: compare first via Zotero vs. EndNote or the wider reference management software comparison, and note that the equivalent install-and-repair page for the main open-source alternative is Zotero setup and troubleshooting. Institutionally licensed web-based managers behave differently again — see RefWorks. This page sits in CASRAI’s research tools cluster.
Frequently asked questions
Do I download Cite While You Write separately?
No. It is a component of the EndNote Desktop installer and is selected by default. If it is missing, the answer is always to repair or re-run EndNote’s own installation — never to look for a standalone plugin, and never to install an unofficial one.
Why did the EndNote tab disappear after a Word update?
Two possibilities, and they have different fixes. Word may have disabled the add-in, in which case the COM Add-ins or Disabled Items route restores it in seconds on Windows. Or the update replaced enough of the Word installation that the add-in has to be written again — the Repair route on Windows, the Customizer on macOS.
Where is the Customizer on Windows?
There isn’t one. The Customizer is macOS-only. The Windows equivalent is the COM Add-ins dialog for re-enabling, and the installer’s Repair/Modify option for reinstalling. Windows instructions that mention a Customizer are describing the Mac product.
Do I need administrator rights?
For re-enabling the add-in in Word (Windows rungs 1 and 2) — no. For repairing or modifying the EndNote installation — generally yes, and on a managed machine that means raising a ticket. Try the two no-privilege rungs first.
Do I have to close Word before installing EndNote?
Yes, and it is the most-ignored instruction in this whole process. Clarivate states it plainly for the Windows Repair/Modify path (“you must make sure that your word processor is not running”) and for the macOS manual bundle copy (“Quit Word. This step is important!”). An install that runs with Word open can finish successfully and still leave no tab.
Will EndNote 21 and EndNote 2025 both work with my Word?
Both support Word 2016, 2019, 2021 and Microsoft 365, and libraries move between the two versions in either direction, so a mixed-version group is not blocked. Feature availability still differs: browser-based CWYW in Word Online and Google Docs requires EndNote 21 or 2025.
My citations insert but the formatting is wrong. Is that an install problem?
No. If the tab is present and citations insert, the add-in is installed correctly and the issue is the output style or the document’s field state. That is covered in the usage walkthrough, with the underlying conventions in citation styles and referencing formats.
Sources checked
Every menu path, precondition and quoted warning above was checked in August 2026 against Clarivate’s own EndNote 2025 documentation, using both the Windows and the macOS trees at docs.endnote.com — specifically the Windows “No EndNote commands in Word or Writer” and Cite While You Write troubleshooting pages, and the macOS “Cite While You Write Installation Problems” and Customizer pages. Compatibility statements were cross-checked against UCL’s EndNote library guide, which maintains the same version and platform detail. Clarivate’s documentation is the authority on anything that has moved in a point release: where a menu label there differs from this page, the vendor documentation wins. Licence pricing is deliberately not quoted, because it varies by institution, seller and region.
