Hey @Steven_Mamet - my best guess is that this was related to an out-of-memory error, although I can't say for sure.
placements.qza (6.0 MB) tree.qza (2.7 MB)
(note: these were computed using a development version of QIIME 2, provenance will reflect that)
Good news - this is slated to land in QIIME 2 2019.10 (we are trying to release that this week). The plan is to allow for SILVA 128 or GG 13.8.
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