The ferry service company has withdrawn MV Hebrides due to a reoccurrence of a problem with its carbon dioxide (CO2) firefighting system. Issues with the firefighting system had first been reported in June.
MV Hebridean Isles had been brought in to cover the Skye Triangle following disruption to sailings on Tuesday and Wednesday last week.
It is the second time in a week the MV Hebrides has been withdrawn from service.
As a result of pulling the service, all sailings on Tuesday and Wednesday between Uig on Skye, Lochmaddy on North Uist and Tarbert on Harris were cancelled.
Issuing an apology, the ferry operator, which runs 34 vessels in the UK, said: "Disrupting a sailing is a decision we do not take lightly because we know it will inconvenience our customers and the communities we serve.
"We apologise for any inconvenience caused.”
Customers have been advised to travel via Lochboisdale-Mallaig or Stornoway-Ullapool, with the company stating that additional services would operate between Lochboisdale and Armadale.
CalMac customers have been warned space on these sailings was "extremely limited" because it was a time of peak summer demand.
Finlay MacRae, head of operations at CalMac, said: "Very regrettably, MV Hebrides has had a reoccurrence of the issue with her CO2 firefighting system and we are sorry to announce that sailings today have had to be cancelled as a result of this. We are currently working on relocating the vessel to a mainland location to allow the necessary specialist teams to effect repairs. We will confirm estimated repair times shortly.
"We recognise that this situation is very difficult and inconvenient for our customers, especially so soon after the most recent disruption, and we sincerely apologise to everyone affected and will do our best to find alternative options where these exist.
"While we know this process is time consuming and frustrating for customers, our staff are doing their very best to help and should not be subjected to aggression or violent behaviour".
MV Hebrides was set to be replaced by one of two vessels at the centre of a ferry-building fiasco at Ferguson Marine shipyard in Port Glasgow.
Kenny MacLeod, who chairs Harris Development Ltd, has written to transport minister Jenny Gilruth following the latest service disruption, saying “urgent action” is needed.
In a letter he wrote: “For too long those with a vested interest in ignoring the wishes of the island communities and sticking with an outdated and inefficient design and operational system have been allowed to squander millions of our [taxpayers] money, and all to the detriment of the communities they are meant to be serving.
“Every cancelled sailing adds more fuel to the funeral pyre and pushes many businesses and residents closer to the edge for packing up and leaving.
“No amount of platitudes or promises can cover over the many years of neglect that are causing the severe injuries we are experiencing. The only remedy is immediate and direct action to save our communities by providing the necessary vessels and funding to allow us to carry on living here.”