Inaccuracies and misplaced towns and cities in Apple's new map software have provoked anger from users.
In June Apple announced it would stop using Google Maps in favour of its own system, created using data from navigation firm TomTom and others.
Apple is yet to comment on the complaints about the software, which comes already installed on the new iPhone.
TomTom said it provided only data and was not responsible for how it worked.
The software is packaged with iOS6, the latest version of Apple's operating system, which runs on the iPhone, iPad and iPod Touch.
Previously, the system had an app running mapping software from Google.
But users are now forced to use Apple's new maps once they upgrade or buy the latest iPhone - which goes on sale on Friday.
There is not currently a Google Maps app available in Apple's App Store, although Google's system is still accessible via the phone's web browser.
Museum in river
Among the user complaints regarding Apple's maps sent to the BBC were:
- Some towns appear to be missing, such as Stratford-upon-Avon and Solihull.
- Others, like Uckfield in East Sussex, are in the wrong location.
- Satellite images of various locations, particularly in Scotland, are obscured by cloud.
- A search for Manchester United Football Club directs users to Sale United Football Club, a community team for ages five and above.
- Users also reported missing local places, such as schools, or strange locations. Another screenshot showed a furniture museum that was apparently located in a river.
The Twitter account which posted the screenshot, @fake_iOS6maps, has since been suspended.
TomTom, which also licenses data to a range of other mobile manufacturers, defended its involvement.
A spokesman told the BBC that its maps provided only a "foundation" to the service.
"The user experience is determined by adding additional features to the map application such as visual imagery," a spokesman said.
"User experience fully depends on the choices these manufacturers make.
"We are confident about our map quality, as selling 65 million portable navigation devices across the world and more than 1.4m TomTom apps for iPhone in the past two years reaffirms this quality."
Prior to the release of iOS6, several developers had expressed concerns over the capability of the mapping app, in particular its ability to find businesses via search.
Spot the difference
"This is incredibly different from using Google Maps," one Denver-based blogger wrote on 13 September.
"It's a tremendous step backwards and something that cripples iOS for Apple's customers.
"I [searched] 'iPhone Repair' and 'iPad Repair' since that's relevant to our business. The results broke my heart.
"All of the work I've put into our local recognition is completely gone."