Sometimes it is acceptable for a removed trustee to refuse to turn over assets, according to the Wills, Trusts & Estates Prof Blog in "Removed Corporate Trustee’s Refusal to Turn Over Trust Assets to Individual Trustee Was Prudent and Appropriate."
Marsha Sinzheimer and her late husband had created a trust for her benefit. The trust documents required that there should be co-trustees, one a corporate trustee and one an individual trustee.
Sinzheimer's son Andrew was appointed to take over as the individual trustee. However, before the former individual trustee stepped down, he exercised his authority to remove the corporate trustee and did not name another one.
When Andrew took over, he demanded that the now former corporate trustee turn over control of trust assets to him, but he was refused.
Andrew Sinzheimer and his mother sued. However, the court determined that the former corporate trustee acted appropriately, because it had refused to turn over the assets until Andrew named another corporate trustee.
That was proper in this case, because Andrew intended to dissolve the trust and in doing so was not considering the interests of the remainder beneficiaries of the trust to whom the former corporate trustee still owed a fiduciary duty.
Reference: Wills, Trusts & Estates Prof Blog (Nov. 13, 2017) "Removed Corporate Trustee’s Refusal to Turn Over Trust Assets to Individual Trustee Was Prudent and Appropriate."