Received 4 new RB260GSP's from my supplier. I am unable to log into the web interface on any of them. I have tried both reset options AND tried to use a router to push latest firmware via tftp to one of them with no success. the device does seem to respond to going into TFTP mode with fast flashing light, but will not pull firmware from the router. Screen grab is below of web interface. I have searched the user forum and cannot find anyone that has been able to resolve this issue. Not feeling warm and fuzzy with four new devices out of the box acting the same way.

I had the same issue with one of mine. I ordered 5 of them (all came with firmware v1.14), and had one of the five unable to load the web interface. I was unable to reload the firmware via tftp, so I ended up getting it replaced. The remaining 4 upgraded to 1.17 just fine. Not sure what the issue is, will have to wait for MikroTik to give some input on this...

I've got 15 of them and none of them will pass the load screen, pass-through internet, or provide POE with a reasonable cable length on it. Any help would be nice. I tried Netinstall but Wine won't run it.

Netinstall is for ROS based products, not SwOS. You need to use DHCP/BOOTP with TFTP.
http://wiki.mikrotik.com/wiki/SwOS
Check at the end of the page....

BTW, have you tried to use another browser?

I'm experiencing this with multiple RB260GSPs I've purchased in the last six months. VERY ANNOYING!!!!

i just thought to react..

I've never encountered the problem lots of people are describing. I unpack, connect, upgrade, configure, deploy.
about POE: I used to have one poe problem on remote location. The poe was running 3 UBNT dishes (pbe400) and sometimes would switch it off. Now im using UBNT injectors. That was early hardware version (if that ever changed, i don't know)
My other POE experience is good, daisy chaining up to 4 RB260GSP in row. No problems. Occasionally i have to replace one which is dead (once a year, mostly water ingress, or failed POE)

I run around 40 of them in outdoor "enclosures" most of which runs over POE and also powers other (e.g. WAP) equipment

I fixed it.

I kinda screwed up. I ordered a used RB260GSP that was unnaturally cheap. I knew it was an old one, and I thought that was the reason... But upon trying to enter the web interface, I quickly realized, that no, that was not, in fact, the reason. It exhibited all symptoms of the bug described here. Web interface stuck on loading, no TFTP upgrade, no matter what I tried. I knew I'd receive support neither from the individual I ordered it from nor from MikroTik. I mean, I certainly wouldn't offer warranty service for a device that was purchased years ago by another person entirely. So I decided to play around with it.

I noticed that, while I entered the address '192.168.88.1' into the address bar, it would redirect me to '192.168.88.1/index.html'. That got me thinking. This was kind of the only way that I could communicate with the switch that worked. What if there were other pages of the web interface that would be functional, to some degree? I entered '192.168.88.1/upgrade.html' into the address bar, and, to my astonishment, I got a form that said 'Choose file...'. So I did. There was no submit button, because, normally, it would be a different part of the page, so I added my own with the 'Inspect Element' feature of <insert modern browser name here>.

I pressed the submit button, the firmware got uploaded, and I got redirected to '192.168.88.1/upgrade', I guess from completing the POST request. I then tried to go back to '192.168.88.1/index.html'. It got garbled with some nonsense data, so for a moment I thought that I'd bricked it further and that the firmware was corrupted beyond repair after all. But I went back to the upgrade page, and it still was fine. I knew I was onto something, so I decided to compare with my other RB260GSP, the new version. I unplugged the old RB260GSP from power. I then plugged in the new RB260GSP, and inspected the interface. I found that the submit button that normally upgrades the firmware also sends a reboot signal to the router. Having a good feeling about it, I unplugged the new RB260GSP and plugged in the old.

It worked. The interface was fully functional.

And now I got a shiny old RB260GSP.