TalkTalk generated £44m of profit in the same period previous year.
TalkTalk has been trying to reinstate its standing as a budget internet provider after its reputation took a hit from a cyber attack in 2015, which saw the personal data of more than 150,000 customers stolen.
In February, Charles Dunstone, who created TalkTalk in 2002, returned as executive chairman in an attempt to renew investors' faith.
But chief executive Tristia Harrison said the firm was delivering on promises made earlier in the year.
TalkTalk said its core earnings for the year would be towards the bottom of its expected range of £270-300mln as it restructures the business in an effort to increase its share of the market in the second half of the year.
The company reported a statutory pre-tax loss of £75mln for the six months to the end of September, compared to a £30mln pre-tax profit past year.
TalkTalk said its broadband base had grown for the third successive quarter and managed to hold onto customers better than it had been doing a year ago. "Our revised strategy of focusing the business on fewer, clearer priorities is re-establishing TalkTalk as the value provider of choice in the United Kingdom fixed connectivity market".
The company took a £59m exceptional charge for costs including £20m associated with "implementing changes to the group's organisational structure under the new leadership team".
"Our clear value proposition is resonating strongly against an uncertain economic environment and underpins our plan to simplify and focus all our investment in delivering affordable, reliable fixed connectivity to both homes and businesses".
"The first half performance shows we are delivering on that plan".
There was also a £31m charge at its mobile business as a result of a strategy review.