Background/Objectives: Post-thaw washing of cryopreserved hematopoietic progenitor cell (HPC) products is performed to remove dimethyl sulfoxide (DMSO) and reduce infusion-related toxicity. Hydroxyethyl starch (HES) has traditionally been used as an osmotic buffer in washing solutions; however, severe regulatory restrictions and market suspensions by the European Medicines Agency (EMA) have limited its availability in Europe. This pilot study evaluated the technical feasibility of utilizing a 4.0% human serum albumin (HSA)-based washing solution to replace HES without compromising post-thaw product quality parameters. Methods: Sixteen cryopreserved peripheral blood HPC bags from eight patients (cryopreserved between 2006 and 2015) were analyzed using a paired experimental design. For each patient, one bag was thawed and washed using the standard HES-HSA solution, while the paired bag was processed using an HSA-based solution. Total nucleated cell (TNC) recovery, TNC viability, viable CD34+ cell recovery, CD34+ viability, and clonogenic potential (CFU assay) were assessed immediately after washing and after 90 minutes of short-term post-thaw storage. Results: No statistically significant differences were observed between the HES-HSA and HSA washing solutions for any evaluated parameter. TNC recovery rates were 86.6 ± 6.6% and 88.9 ± 7.9% for the HES-HSA and HSA groups, respectively (p = 0.54). Post-thaw viability, viable CD34+ cell recovery, CD34+ viability, and clonogenic potential were stable and comparable between both processing strategies. Conclusions: An albumin-based washing solution provides cellular recovery, viability, and clonogenic performance comparable to conventional HES-containing formulations in a laboratory setting. Given current restrictions on HES due to clinical safety concerns, an albumin-based formulation represents a practical and logistically viable operational alternative for the post-thaw processing of peripheral blood HPC products.