Tony Pulis admitted Middlesbrough have been left weaker in some areas following a disappointing January transfer window.
Boro didn't make a single signing on deadline day, despite the fact Pulis wanted to bolster his attacking options.
The Teessiders had signed John Obi Mikel and Rajiv van La Parra earlier in the window, but lost forward Martin Braithwaite and defender Danny Batth in January.
And the club's lack of activity left Boro supporters extremely frustrated, with the club pushing for promotion from the Championship.
Pulis was also extremely disappointment and gave an honest pre-match press conference ahead of Boro's trip to West Brom this weekend.
"I think everybody around the club will be disappointed," said Pulis.
"There’s no hiding the fact there were players we wanted to bring in who we haven’t been able to bring in.
"There are areas I’ve wanted to strengthen for 13 or 14 months and we’ve not been able to do that.
"It’s been a window where in some respects it’s made the team weaker than stronger.
"I've had three windows here and I've signed three permanent players, you're hoping and praying to do more than that."
Boro were linked with moves for Newcastle winger Jacob Murphy and Hull wideman Kamil Grosicki but missed out on both on the final day of the window.
Pulis didn't lay the blame on Boro chairman Steve Gibson, who has backed the club heavily since their relegation from the Premier League.
Even so, Pulis is amazed at some of the wage figures the club are paying.
"I’ve got to say two things: I think the club has got an exceptional person in charge in Steve," said Pulis
"The money and what he’s done is extraordinary.
"For one individual to back the club the way he has, there’s no criticism whatsoever in that area."
When asked if he was angry at Boro's lack of business in January, Pulis replied: "Not angry, disappointed more than anything else.
"Disappointment in reflection of what was spent 18 months ago or whatever it was.
The wages and everything else is extraordinary. The club is paying for it at the moment."