Jiaxing -
Thank you for the response, here are the details you requested.
First, here is the file structure I am working with, and the file that has the error is the "LGS 3YR Budget v9.1.xlsx":

I proceed to open the file, and select "ignore links" upon opening to allow the file to open cleanly.

Once in the file, I select "Data/Edit Links" to get to the following screen:

The first two links are the issue, the third link I was able to change and it works properly. The first two links were created on a different computer, as you can see, and were built under Office for Mac 2011 (note I am using the current Office 365 Home
version). The first two files, however, have been opened and resaved using the current version of Excel and as a stand alone file work just fine.
Then I select either of the first two links and click on "Change Source":

On this screen, I select the proper file in the correct location on my computer, and then click "Change". When I do that, I get the following error message stating the file cannot be found, despite the file actually being in that location:

Now the "Change" button changes to "Copy", which does not work either. If you continue to select the file and click the "Copy" button I continue to get the "cannot find" dialogue box.
At this point the only way to exit this is to click "Cancel", which causes Excel to crash and brings up this dialogue box:

Please note, that other files with external links are working properly, as is the third link in the file I am working with (shared above). If you would also like the "More Information" crash report please let me know and I will send that to you too.
Hopefully this is helpful and I look forward to your response.