Construction projects have become more complex over time, and cost overruns and time delays have become a global phenomenon. Signs that can indicate future project failure, such as cost overruns and time delays, in early project phases are Early Warning (EW) signs. EW signs are defined as indicators for potential future problems. This research investigates mechanisms that influence the response to EW signs in construction projects. Directions for solutions to mitigate the obstructions for responding to EW signs found in this research are also provided. This research provides a new perspective compared to current literature, by conducting research from the perspective of a contractor, including the interaction with subcontractors. Previous studies focused on the client’s perspective instead. This qualitative research uses a combination of research methods including an in-depth case study on the EW response of three constructions projects, expert interviews and an expert meeting. Data analysis in this research uses grounded theory methodology, and combines organisational behaviour theory with the topic of EW signs. Two main mechanisms influencing the EW response were found: (1) the lack of information flow in projects seems to prevent EW signs from being identified, and (2) group culture and team interaction were found to hinder the response to EW signs in projects. A third mechanism was found as a recurring theme impacting three out of four analysed EW responses: interpretations of agreements and contracts, and trust in the work carried out by other parties seem to reduce the activity of identifying and responding to EW signs. To mitigate the obstructions for identifying and responding to EW signs found in this research, the following directions for solutions are concluded to show potential: attention for individual characteristics in team composition, equipping the information system in projects with accessible options to store, and keep track of potential EW signs during projects, increasing the attention to EW signs during the tender phase, and creating awareness of the importance of responding to EW signs in project teams.