"Missing" photos in Develop mode only after updating Catalog

Recently updated LRC to v13 which requires your old catalogs to then be updated to a new version in order to be opened and capatible. However, since doing this I am no longer able to edit my photos because in the Develop mode it says "This file cannot be found"   Typically if this were true, and they really needed to be located there would be an exclamation point on the thumbnails and there is not. While In the library mode I can use the drop down from the top to use the button "find all missing photos" -  it then pops up to say "No Missing Photos. All photos in this catalog are available" 

I even moved a handful of photos from to a new folder on my external hardrive to simulate them actually needing to be found. This did generate the exclamation point for me to then show lightroom where the photos are located. Typically if all my photos are missing and I manually locate one picture it will automatically register where all the photos are located (if the entire batch is in the same folder) and I can move forward with editing under the develop module- this is not working either. It did register where the one photo was when I manually showed it, and for the library itself it automatically registered where the other photos were as well and therefore the exclamation points disappeared from all photo thumbnails but it did not work for the photos once I tried to move to the develop mode. It continued to say they were not found. The only photo i could move forward with editing was the individual photo that I moved and then showed the system manually where it is. 

Please help. I cannot afford to be going through this with literally every single photo from every single catalog. Especially the catalogs that I am in midprocess of editing.