Convert feature class names to lower case?

Question

I'm simply trying to loop through the first immediate set of folders in a directory, then the GDB's, and finally the feature classes, however, now I get "ERROR 000840: The value is not a Data Element. Parameters are not valid" for random feature class names that are being converted. For instance, it will convert one feature class named "S_WTR_LN" to lower case but will recieve the error with a feature class named "S_GEN_STRUCT". This happens when it reaches line 25, at the first arcpy.Rename_management.

UPDATE: Somehow there was a lock in arc catalog. After reseting everything, it worked -_- Final working code is below for reference.

import arcpy
import os

rootdir = r'\\server\test\ARCHIVE\\'


for subdir in os.listdir(rootdir):
    path = rootdir + subdir
    arcpy.env.workspace = path
    databases = arcpy.ListWorkspaces("*", "FileGDB")

    for database in databases:
        arcpy.env.workspace = database
        fcList = arcpy.ListFeatureClasses()
        for fcName in fcList:
            if fcName.islower():
                pass

            else:
                fcLCName = fcName.lower()
                arcpy.Rename_management(fcName, 'TEMPNAME', 'FeatureClass')
                arcpy.Rename_management('TEMPNAME', fcLCName, 'FeatureClass')

Answer 1

I'm not able to test this but I tweaked a couple things:

1. Leave off the trailing backslashes in rootdir
2. Use os.path.join to join rootdir and subdir

import arcpy
import os

rootdir = r'\\server\test\ARCHIVE'

for subdir in os.listdir(rootdir):
    path = os.path.join(rootdir, subdir)
    arcpy.env.workspace = path
    databases = arcpy.ListWorkspaces("*", "FileGDB")

    for database in databases:
        arcpy.env.workspace = database
        fcList = arcpy.ListFeatureClasses()
        for fcName in fcList:
            if fcName.islower():
                pass
            else:
                fcLCName = fcName.lower()
                arcpy.Rename_management(fcName, 'TEMPNAME', 'FeatureClass')
                arcpy.Rename_management('TEMPNAME', fcLCName, 'FeatureClass')

See if that works. I'm not really sure what else would be causing the error you mentioned.