Sometimes, even though you have downloaded Zotero, the Zotero toolbar does not appear in Microsoft Word. Here are several common troubleshooting tips.

1. Make sure all of your Word documents are closed. After closing all of the Word documents you may have been working on when you downloaded Zotero, reopen a document. Hopefully, you will now see the Zotero toolbar.

2. Reinstall Zotero. Return to the Zotero downloads page and reinstall the Zotero library. This will not delete the information you have currently saved in your Zotero library. Follow the menu prompts that indicate that you would like to save the data from your current library.

3. Reinstall the Word add-in via the Zotero Preferences menu. On a PC within your Zotero library go to the Edit menu, then select Preferences (on a Mac select Zotero and then Preferences). Within Preferences, choose the Cite tab. Within the Cite tab, choose the Word Processors tab. Select the Install Microsoft Word Add-In button.

My recommendations come from this forum post, so feel free to just refer to this post (or use it in addition to my suggested steps below):

1. Reinstall Zotero. First make sure you have entirely closed Word and Zotero. Use the download instructions to re-install your Zotero library.

2. Open up Word and see if the Zotero icons are there. If not, from within Word, see if the Zotero.dot file is in your Word startup folder. If it’s not there, search for that file (it may be in your Office 2011 start up folder), and once you find it, move it to the 2016 start up folder – then Zotero and Word will know where to look for it. Re-start Word.  – Here are the step-by-step directions if you haven’t played around with finding support files before:

1- Open Word
2 - Click on "Word" in bold next to Apple in the Mac applications menu (https://support.apple.com/en-ca/HT201956)
3- Select Preferences in the drop-down options
4- Click on File locations under Personal settings
5- Click on "Start up" at the bottom of the list
6- Click "modify'" and select ~/Library/Group Containers/UBF8T346G9[where UBF8T346G9 is a random string that will be different on your computer and should already exist] .Office/User Content/Startup/Word