I used epoxy without much fuss and I never used it before and only tiled once before in my life when I did my small kitchen backsplash area last year. So laticrete epoxy isn't that hard, honest. Once its done, your done, and you will have a durable grout. Have you considered urethane grout? It needs a 7 day cure time, without use, but other than that I've heard good reports. It is pre-mixed and the container can be recovered for use later; how long, I don't know. A high end tile shop in my locale uses it for their display floors because of the ease in use and the ability to cover and save. It is a Hydroment brand that they use. I have used the Hydroment thinset and have been very pleased with the product. They make the Ditra-Set that I used for my Ditra installation. Regarding Laticrete SpectraLock: What I did for my floor grout was mix a custom color with laticrete spectralock colors Platinum and Silver Shadow and some other grays. I did some small mixing with the small cartons of color you can get at Lowes, but I only purchased one tub of the epoxy. I prepped all my dry color combos and kept records. Then I mixed the epoxy and divided into small disposable containers mixing the dry into each. Ultimately, I came up with a 3part platinum and a 1part silver shadow that I used on my floor. I am very happy with it. I bought a large sized Laticrete kit of the Platinum online, that was linked through the Laticrete web site. I then bought a small carton of just the dry Silver Shadow color at Lowes and measured this SS amount, removed that same amount from the Platinum then added the SS. The large kit is equal to 4 small kits. So that was my 3:1 ratio. Of note the Laticrete Spectralock in the small cartons at Lowes is the "Spectralock Premium" and the large kit I got on line was the "Spectralock Premium Pro". The colorants are all the same, the epoxy, parts A&B are what differs. The Pro I think is a newer product and maybe has better application properties. As I said I ordered mine online, but you may be able to get the Pro version through special order at Lowes. Here is my finished grout, Silver Shadow on the left and Platinum on the right, My custom is the grout in the tile:

Does the edge of the insert that will be exposed look ok? Or will it look dull/unfinished? If it looks ok, then go for it. I just did a shower with a pewter-colored band that sticks out from the ceramic I used on the rest of the shower. I'll caulk the little step-up from one to the other, but they won't interfere with someone showering. On a floor, it would be a different story. BTW, I am neither god nor guru, just a gal who's on her 4th bathroom remodel in a year and a half.

On many/most/all thumb drives there is a tiny LED light, do you see it with yours? Right click Start click Open Windows Explorer In the new window look down the left side for your thumb drive, possibly showing as the F drive. When you insert the thumb drive is there an audible signal? When you remove it is there an audible signal? What happened when you visited the link Zep provided? Simply saying you tried everything is not helpful, a more detailed reply could help considerably. Chuggerguy asked if you daughter had a Mac or Linux program. Does she? Did she format the thumb drive? These are normally formatted in FAT format.

Here is a previous post that may help. Here is a link that might be useful: LRV