Is there a limit on how many categories or items can be imported?

Hi,

On your video I can see that you're comparing the listing of categories of a category in HikaShop (which is empty as there are no subcategories) with the listing of products of a category in MijoShop (which contains many products).
You need to go in the menu Products>Products to access the listing of products and there you can use the left category explorer to access the products of that category. Then you can compare the two.

While there is no limit for the number of products or categories it can import, it's potentially possible that some products / categories could not be imported due to some bugs or changes that were made in MijoShop.
Since MijoShop hasn't been supported for a while, not many people used the import tool for a while so I wouldn't be surprised that there would be some issues with it.