Excel 2016: this workbook contains links to one or more external sources that could be unsafe

I get this message sometimes when opening a workbook. Often the reason is that I have copied a formula from another workbook (instead of a value).

First I always want to check where these links are before modifying and possible breaking things.

I used a Microsoft support article (ignored the Edge borwser promo) to find the external links:

1. Type CTRL+F (opens Find and Replace Window)
2. Click [Options >>]
3. Fill in these values:
1. Find What: \[
1. the MS article uses [, but I got some false positives from that
2. Within: Workbook
3. Look in: Formulas
4. Click [Find Next] to search

If after verification of these links you want to get rid of the warning, use the advice you get when you click the Help button in the warning message box. In other words:

1. On the Data tab, in the Connections group, click Edit Links
   Here you can optionally update (and break) the links, but you do not see in which cells they are used (that is why I searched for them first).
2. Click [Startup Prompt...]
3. Select the option that you want