I’m trying to run sen2cor 2.10.01’s L2A_Process command on an older product (S2A_MSIL1C_20170811T085601_N0205_R007_T35TME_20170811T090657, it’s the 14.2 baseline) and it fails out with “Product metadata file cannot be read”. I can run 2.09.00 on the same directory without issue. Both are using their respective default sen2cor configs, and this is running on Linux. If it helps, this was downloaded using the sentinelhub Python package, latest version - I would normally blame that package, given the changes in the 14.9 baseline, but I can’t explain why 2.9 would work but 2.10 wouldn’t. I am able to run both 2.9 and 2.10 against a more recent product (S2A_MSIL1C_20220120T091311_N0301_R050_T35TMG_20220120T111422) without problems.
I confirm that I recieve the same message as you when I uses 2.10. But I am able to process the L1C Tile (S2A_MSIL1C_20170811T085601_N0205_R007_T35TME_20170811T090657.SAFE) with 02.08.
I have checked the L1C in SNAP and it appears to be OK in its formatting. I will check the Product metadata against a more recent product.