Staff at Kapille in the High Street have no way of knowing when customers are booked in so are unable to make any new appointments in case they make a double booking.
They cannot even phone clients to find out when they are booked in as the diary, contained on a laptop taken during the burglary, included all contact details.
A back-up memory stick, kept in a separate place to the laptop, was also stolen.
The salon is run by Jenna George and Hannah Hutton, who also employ three stylists. They say the theft has caused chaos and they are working round-the-clock to get back to normal.
The break-in took place around 10pm on Sunday 31st August. Three pairs of hair straighteners, a hairdryer and coins from the till were also taken.
Jenna, 30, said: “The laptop had records going back more than nine years. The database contained details of more than 1,000 clients including their appointments, telephone numbers and hair colour history.
“We had appointments booked in right up until at least January and there were several days in December which were already fully booked. Without knowing who is booked in and when, it is impossible for us to take any new bookings as obviously we cannot risk double booking as this would cause chaos.”
Hannah, also 30, said the alarm was raised after a neighbour spotted someone entering the salon via a smashed glass panel in the front door.
She said: “If anyone with an appointment with us, we would be really grateful if they could ring us on 0117 377 4073 to let us know when they are booked in. We hope our clients will understand and we want to let them know we are working flat out to get back on our feet and get things running smoothly again.”