Here is the original post regarding this problem by lexiphillips on an Apple forum:
Posted Oct 2, 2013 2:08 PM
"Ever since updating my iPhone 5 with the new iOS 7, this display message pops up while my phone is plugged in to the computer, using the original cable that came with it in the box. Researching this issue only informed me that the new iOS is no longer compatible with generic iPhone chargers. However, mine is the one made by Apple and so there should be absolutely no issues with it. While it is plugged in my phone charges on and off, never consistently charging. It's really irritating and is making charging a very slowgoing process. Does anyone else have any insight on this issue?
While we're at it, I noticed the new iOS 7 kills the battery life much faster than the previous iOS; I don't use my phone too much throughout the day, and it has been dying consistently twice a day. If I don't use it nearly at all, it seems to last only six or so hours.
Thanks in advance for any feedback! Hope not everyone is having these issues!
Alexis"
Well Alexis, I am having the same problem all of a sudden (and despite your hopes, it appears that everyone else is a well) and of course it is happening while traveling (again). My iPhone 5C ($700) started displaying the message, "This accessory may not be supported", about a week ago when plugged into my Mac and my IOGEAR High Capacity Portable Battery (GMP6600P).
Here is a synopsis of my impression of Apple products and some of the threads contained herein:
1) When you pay top-dollar for a product, you should not have all of the problems, including this one, I have had with Apple products (iPhone and Macs)
2) We don't care how intelligent or tech-savvy you are, so please provide helpful comments that don't take a PhD in computer science to decipher
3) Apple obviously enjoys trapping its customers into buying only their products and having to replace parts soon after the warranty expires. It's obvious that the Chinese junk they sell is not worth the price-tag.
4) Apple also confiscates our personal information (e.g. photos and God knows what else), making it extremely difficult to take control of them again and holding us hostage by forcing us to purchase more of their products. The latest iOs is a perfect example, sucking up GBs of space on our phones and forcing us to purchase an iCloud data plan (which I refuse to do).
BOTTOM LINE: Apple sucks and I'm going to find a way to save MY INFORMATION on MY external hard drive so that when my iPhone and Mac go tits-up, likely very soon, I can buy a less costly and more reliable product that allows me to travel stress-free and purchase the peripheral devices/accessories of MY CHOICE!
CombatCritic Gives The Apple iPhone 5C A Dismal 1 Bomb Out Of 10 ... More Bombs Are Better!
Title: Apple Still Sucks ... More iPhone Problems: "This accessory may not be supported"
Key Words: Apple, iPhone, 5C, This accessory may not be supported, forum, technical, problem, problems, customer, service, accessory, supported, support, CombatCritic, review, TravelValue, travel, value