Residents living in university-owned homes have been told they will have to leave their houses by the end of February.
Those staying in the previously Rowett Institute-owned houses in Bucksburn, including Eastside Gardens and Walton Road, were originally given notice in June that they may have to leave their properties.
They appealed to Aberdeen City Council in the hope the authority would buy over the homes using Scottish Government legislation.
However, several months later, it has come to a decision that this will not be possible.
As a result, Aberdeen University will now proceed with its original plan to sell the houses, which were acquired in 2008 when it bought over the Rowett Institute.
Residents have been given until the end of January or February to find a new place to stay.
A university spokeswoman said: “Following discussions with Aberdeen City Council regarding the potential purchase of some, or all, of the properties on Walton Road and at Eastside Gardens, we have unfortunately been unable to reach an agreement on their sale.
“As a result, the university is now required to take forward the sale of the properties, as indicated in our previous correspondence to tenants.
“The expected timescale detailed on the notices for leaving the properties will be around the end of January or February 2020, depending on individual circumstances.
“The university has notified tenants of the latest developments and we have offered practical assistance that might assist in their discussions with alternative housing providers.
“Formal notices will be issued in due course and the option of tenants buying individual properties still remains.”
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Aberdeen Donside MSP Mark McDonald, who has been supporting those in the area, said: “Following nineteen weeks of uncertainty, Rowett Aberdeen University tenants need both the university and the council to act quickly to establish a support network of key agency representatives so they can discuss their future housing options and assess what further support they may require as a matter of urgency.
“With winter and Christmas fast approaching, the protracted delay in reaching this decision will leave tenants facing a festive period filled with stress and anxiety.”
An Aberdeen City Council spokeswoman said: “Aberdeen City Council was asked to consider the purchase of a number properties at the Rowett by Aberdeen University. Aberdeen City Council has declined the purchase of the properties having undertaken a value-for-money appraisal.
“In addition to the market value for the property, consideration was given to future council rental income, future maintenance and management costs, works required to bring the properties to Scottish Housing Quality Standard (SHQS) and energy efficiency standards; and any grant support available.”