Zotero’s reference-management core (collections, tags, citing while you write) is covered in Zotero for Researchers. This guide is narrower: it walks through installing and fixing the three pieces that most often break — the browser Connector, the Word/LibreOffice/Google Docs citation plugin, and library sync — with a symptom-to-fix table for the errors researchers hit most. Steps below are checked against Zotero’s own documentation at zotero.org/support as of August 2026; Zotero ships frequent point releases, so if a menu label has moved, the linked official page is the authority.
Zotero’s three parts, in one paragraph
Zotero is free and open source, built by the nonprofit Digital Scholar (formerly the Corporation for Digital Scholarship). It has three components, all free: the desktop app (Windows, macOS, Linux) where your library actually lives; the Zotero Connector, a browser extension that captures bibliographic metadata (and PDFs, where accessible) from a journal page, database record, or search result with one click; and an optional zotero.org account that syncs your library across devices. Library metadata syncs free and unlimited; only attached files (PDFs, snapshots) draw against a separate storage allotment, covered below.
Installing the browser Connector
Download the desktop app first from zotero.org/download — the Connector works best alongside a running desktop install, and on Safari it’s actually bundled with it rather than installed separately.
- Chrome: install the Zotero Connector from the Chrome Web Store (linked from the Zotero download page). Chrome will prompt for permission to read and change data on websites — this is what lets the Connector detect citation metadata on the page you’re viewing; accept it or the save button won’t function on any site.
- Firefox: install from Firefox Add-ons, same download page. Firefox may show an “Allow this extension to run in Private Windows” toggle in about:addons if you routinely browse databases in a private window — enable it there if saves silently fail only in private browsing.
- Edge: Edge accepts the Chrome Web Store version of the Connector directly (Edge is Chromium-based); install it the same way as Chrome and grant the same site-data permission.
- Safari: unlike the other three browsers, Safari does not support installing the Connector as a standalone download — it ships bundled inside the Zotero desktop app and has to be switched on manually. After installing and opening Zotero at least once, go to the Safari menu > Settings (not “Safari Extensions…”) > Extensions, and tick the checkbox next to the Zotero Connector. Safari will show a broad-looking permissions warning (it can read data on all pages, similar wording to what a password manager would request) — that’s Safari’s standard extension permission framework, not something specific to Zotero, and the Connector only uses it to detect and save citation metadata.
After installing, confirm it’s working: open a journal article page or a Google Scholar / PubMed result and look for the Connector’s save icon in the toolbar. It changes shape depending on what it detects (a page icon for a single item, a folder icon on a search-results list for saving several at once). If the icon is grey/inactive rather than showing a recognizable icon, the Connector hasn’t identified a citable item on that page — that’s expected on a homepage or non-bibliographic page, not a bug.
Installing and repairing the word-processor plugin
Zotero has native, official integrations for Word, LibreOffice/OpenOffice, and Google Docs — no separate purchase, but each has its own install/repair path.
- Word and LibreOffice: Zotero installs its own toolbar/tab automatically the first time you launch Zotero after installing the desktop app, provided Word or LibreOffice isn’t open at the same time. If it doesn’t appear, go into Zotero’s preferences, open the Cite pane, and use the Word Processors tab’s “Reinstall” (or “Install [Word/LibreOffice] Add-in”) button, then fully restart the word processor.
- Google Docs: no plugin install at all — with the Connector active and you signed into a Google account, opening a Google Doc adds a Zotero menu directly inside Docs’ own menu bar. This is the only one of the three reference managers in CASRAI’s comparison set with a native, first-party Google Docs integration; see Reference Management Software Comparison for how Word/LibreOffice/Google Docs support differs across Zotero, EndNote, Mendeley, RefWorks, and Paperpile.
Troubleshooting table: symptom to fix
| Symptom | Likely cause | Fix |
|---|---|---|
| Connector icon greyed out on every page, not just non-bibliographic ones | Desktop app isn’t running, or Connector lost its link to it | Launch the Zotero desktop app and leave it open; the Connector talks to a local Zotero process, it doesn’t save straight to the cloud. |
| Connector button visible but nothing saves when clicked | Site permission wasn’t granted, or an ad blocker/privacy extension is interfering | Re-check the browser’s extension permissions for the Connector (site data access), and temporarily disable ad-blocking extensions on the page you’re saving from. |
| “Word could not communicate with Zotero. Please ensure Zotero is running.” | Zotero desktop isn’t open, or the plugin lost its connection after an update | Restart Zotero, then Word. If it persists, delete Zotero.dotm from Word’s Startup folder and reinstall the add-in from Zotero’s Cite preferences. |
| No Zotero tab/toolbar in Word at all | Add-in is disabled or listed as inactive in Word | In Word, go to File > Options > Add-ins. If Zotero appears under “Inactive Application Add-ins,” select and enable it; if it’s under “Disabled Items,” re-enable it from there. |
| Zotero tab present but buttons don’t respond (Windows) | Macro/trust settings are blocking the add-in, or a corrupted install | Check File > Options > Trust Center > Trusted Locations includes Word’s startup folder; otherwise delete Zotero.dotm and reinstall. Confirm neither Word nor Zotero is running as administrator, since a permission mismatch between the two blocks communication. |
| LibreOffice toolbar buttons unresponsive | Missing Java Runtime Environment, or a corrupted LibreOffice user profile | Install a current JRE, then reinstall the Zotero LibreOffice add-in. If that doesn’t resolve it, close LibreOffice and rename/delete its user profile folder so it regenerates. |
| Safari Connector doesn’t appear in the toolbar at all | The extension was never switched on in Safari’s settings (it isn’t enabled by default the way a downloaded extension would be) | Safari menu > Settings > Extensions > tick the Zotero Connector checkbox. If it’s missing from that list entirely, reinstall the Zotero desktop app, since the Safari extension ships inside it. |
| Library not updating on a second device / “zotero storage limit” errors | Sync is either not enabled, credentials expired, or attached files have exceeded your paid/free storage allotment | Check Zotero preferences > Sync for a working zotero.org login and a recent successful sync time. If the error specifically references storage, see the storage section below — metadata sync is unaffected by storage limits, only file attachments are. |
| Duplicate citations or “Add Citation” pulls the wrong version of a source | Two library copies (e.g. a local unsynced item and a synced duplicate) exist after working offline on two machines | Run Zotero’s built-in Duplicate Items view (left sidebar) and merge; then let a full sync complete on both machines before citing again. |
Sync, storage limits, and the WebDAV alternative
A zotero.org account syncs your library metadata — items, notes, collection structure — for free with no storage cap. Attached files are the part that counts against storage: the free tier is 300 MB, with paid tiers at 2 GB for $20/year, 6 GB for $60/year, or unlimited for $120/year (verified against zotero.org/storage). If you’re hitting a “zotero storage limit” message, your options are upgrading the storage tier, removing large attachments you don’t need synced (Zotero can still sync the metadata-only record), or switching file sync to a WebDAV server you control instead of Zotero’s own storage — configurable in Zotero preferences under Sync, under the file-syncing section. WebDAV shifts file storage to your own server or a WebDAV-compatible provider, at whatever capacity that server has, while item/note metadata still syncs through Zotero’s own free service either way.
Group libraries
Group libraries let a lab or grant team share a working bibliography. Create one from the desktop app (File > New Library > New Group) or from the zotero.org groups page. There are three types: Private (invisible to anyone outside the group), Public closed-membership (visible, but joining requires an invite or admin approval), and Public open-membership (anyone can join instantly, though open public groups don’t support shared file/PDF storage). Group file storage draws against the group owner’s individual storage plan, not each member’s. For the fuller workflow — structuring collections, tagging, PDF annotation, and using a group library day to day on a grant — see Zotero for Researchers.
Migrating from Mendeley or EndNote
Elsevier has wound down active development of the classic Mendeley Desktop app in favor of the web-based Mendeley Reference Manager, and new installs are steered toward Reference Manager rather than Desktop. That transition is a live source of migration traffic toward Zotero: Reference Manager’s full-text PDF search and some of Desktop’s annotation tooling have lagged behind what the original desktop client offered, which is the specific complaint that tends to send researchers looking at alternatives. If you’re moving a library over:
- From Mendeley: export your Mendeley library (File > Export, choosing RIS or BibTeX) and import the resulting file into Zotero via File > Import. PDFs attached in Mendeley need to be re-linked or re-downloaded on the Zotero side, since the export formats carry citation metadata, not the file attachments themselves.
- From EndNote: export your EndNote library as EndNote XML or RIS (File > Export in EndNote), then use Zotero’s File > Import on that file. EndNote XML preserves more metadata fidelity than RIS if your library uses custom fields or extensive notes.
- Either way: import into a new, empty Zotero collection first rather than your main library, check a sample of items for correctly mapped item types and author names, then run Zotero’s Duplicate Items view before merging into your working library.
For a fuller side-by-side on cost, institutional licensing, and where each tool is actually stronger, see Zotero vs. Mendeley and Zotero vs. EndNote.
Which reference manager should you use?
“Best reference manager” doesn’t have one answer — it depends on whether you need free/open-source software, an institutional EndNote or RefWorks license, native Google Docs support, or heavy PDF annotation. CASRAI’s comparison pages go through this trade-off directly: Zotero, EndNote, Mendeley, RefWorks & Paperpile compared, Zotero vs. Mendeley, and Zotero vs. EndNote. Zotero itself is free with no institutional license required, which is why it’s the tool this page and Zotero for Researchers focus on.
Frequently asked questions
Why isn’t my Zotero Connector saving anything?
Almost always one of two things: the Zotero desktop app isn’t open (the Connector needs a running local Zotero process to save to), or the browser hasn’t granted the Connector permission to read the page’s data. Check both before assuming it’s a bug.
How do I fix Zotero not working in Word?
Restart Zotero and then Word, in that order. If the tab is still missing or unresponsive, reinstall the add-in from Zotero’s Cite preferences (Word Processors tab), and if that fails, manually delete Zotero.dotm from Word’s Startup folder before reinstalling — see the troubleshooting table above for the specific error-message variants.
What is Zotero’s storage limit?
300 MB free for attached files, with paid tiers at 2 GB, 6 GB, or unlimited (verified against zotero.org/storage, pricing subject to change — check that page directly before budgeting). Item and note metadata sync free and unlimited regardless of the file-storage tier; only attachments count against it.
Does Zotero work with Google Docs?
Yes, natively — it’s the only one of the major reference managers in CASRAI’s comparisons with a first-party Google Docs integration, added automatically through the Connector with no separate plugin to install.
Can I use Zotero instead of Mendeley Reference Manager?
Yes; export your Mendeley library as RIS or BibTeX and import it into Zotero. See the migration section above for the full sequence, and re-attach or re-download PDFs after import since exported metadata files don’t carry the attachments themselves.
Steps and figures on this page were checked directly against Zotero’s own documentation (zotero.org/support) and Zotero’s storage pricing page (zotero.org/storage) in August 2026. Zotero updates its interface between versions; if a menu path here doesn’t match what you see, the linked zotero.org page is the current authority.
