Methods and apparatus for accessing dispersed storage error encoded data in a dispersed storage network (DSN). When storing data in available storage units of a DSN, a DS processing unit issues a write slice request that includes a slice name corresponding to the storage unit and a unique encoded data slice of the set of encoded data slices, where each encoded data slice includes an IDA index of the corresponding storage unit. For each unavailable storage unit, the DS processing unit issues a write imposter slice request to a foster storage unit that includes a slice name corresponding to the foster storage unit and imposter encoded data slice corresponding to the unavailable storage unit, where the imposter encoded data slice includes an IDA index corresponding to the unavailable storage unit.