8000 files. Average about 4mb. The total is about 29gb.

@ferdinand
Thank you for your response and suggestions.

I created a script version of my plugin, but it still crashed after running out of memory. Here it is in the bare bones version paired down to simply loading all the files into a list, opening them and closing the file. My included screenshot shows the memory load increasing till I run out of memory. How do I avoid this?

import c4d, math, string
from c4d import gui, plugins, utils, bitmaps
import os


# Main function
def main():
    
    filesList = []
    initialPath = "/Volumes/Argo3D/"
    rootDir = c4d.storage.LoadDialog(c4d.FILESELECTTYPE_ANYTHING, "***** -PLEASE CHOOSE THE DIRECTORY ROOT- *****", c4d.FILESELECT_DIRECTORY, "", initialPath) + "/"

    findText = c4d.gui.InputDialog("Enter the text to find (To replace)", "")
    if findText == "":
        c4d.gui.MessageDialog("No FIND text entered")
        return
    replaceText = c4d.gui.InputDialog("Enter the text to replace the found text", "")
    if replaceText == "":
        c4d.gui.MessageDialog("No REPLACE text entered")
        return

    for root, subFolders, files in os.walk(rootDir):
        for file in files:
            if file[-4:] == ".c4d":
                pathWithFile = root + "/" + file
                filesList.append(pathWithFile)

    for fixFile in filesList:
        changed = False
        c4d.documents.LoadFile(fixFile)
        doc = c4d.documents.GetActiveDocument()
        c4d.documents.InsertBaseDocument(doc)
        c4d.documents.SetActiveDocument(doc)
        c4d.documents.SaveDocument(doc, fixFile, c4d.SAVEDOCUMENTFLAGS_0, c4d.FORMAT_C4DEXPORT)
        c4d.documents.KillDocument(doc)
    c4d.gui.MessageDialog("Done!")


    c4d.EventAdd()

# Execute main()
if __name__=='__main__':
    main()

My plugin searches for and replaces strings of text in xrefs. It first gathers into a list all xref c4d files from a designated directory tree. If the directory contains more than a hundred or so legacy xrefs, which have several embedded xrefs, the plugin crashes.
Two questions:

1. Based on my supplied code, is there a way to optimize what I have to avoid crashes?
2. Is there a way to flush the cache after every directory of files processed? I've tried cache_clear() with no luck.
   Here are, hopefully, the relevant parts of my code:

def GetVirtualObjects(self, op, hierarchyhelp):
        dirty = op.CheckCache(hierarchyhelp) or op.IsDirty(c4d.DIRTY_DATA)
        if dirty is False:
            return op.GetCache(hierarchyhelp)

        baseNull = c4d.BaseObject(c4d.Onull)
        pluginNode = c4d.BaseObject(c4d.Onull)
        pluginNode.InsertUnder(baseNull)

        c4d.EventAdd()
        return baseNull

def Process_Process(self, op, rootDir, findTextList, replaceTextList, simulateFolderOnOff, simulateFolder, logFile_OnOff, logFileFolder):
        filesList = []
        now = datetime.now()
        logReport = ("Date: " + now.strftime("%m-%d-%Y") + '\n' + "Time: " + now.strftime("%H:%M:%S") + '\n' + '\n')

        for root, subFolders, files in os.walk(rootDir):
            for file in files:
                if file[-4:] == ".c4d":
                    pathWithFile = root + "/" + file
                    filesList.append(pathWithFile)

        changed = False
        for fixFile in filesList:
            c4d.documents.LoadFile(fixFile)
            doc = c4d.documents.GetActiveDocument()
            c4d.documents.InsertBaseDocument(doc)
            c4d.documents.SetActiveDocument(doc)
            logFile = True

            xList = []
            Selected = self.get_all_objects(doc.GetFirstObject(), [])
            for ListOb in Selected:
                theType = ListOb.GetTypeName()
                if theType == "Legacy XRef" or theType == "Simple XRef":
                    if ListOb[c4d.SCENEINSTANCE_FILENAME] != None:
                        xList.append(ListOb) #Build xref list
            for y in xList:
                xrefNameAndPath = y[c4d.SCENEINSTANCE_FILENAME]
                originalXrefNameAndPath = xrefNameAndPath
                for x in range(10):
                    if findTextList[x] != "":
                        finalXrefNameAndPath = self.ireplace(findTextList[x], replaceTextList[x], xrefNameAndPath)
                        if xrefNameAndPath != finalXrefNameAndPath:
                            y[c4d.SCENEINSTANCE_FILENAME] = finalXrefNameAndPath
                            if logFile == True:
                                logReport = (logReport + "File: " + fixFile + '\n')
                            logFile = False
                            xrefNameAndPath = finalXrefNameAndPath
                            changed = True
                if changed == True:
                    logReport = (logReport + "Original Xref Name: " + originalXrefNameAndPath + '\n' + "New Xref Name: " + finalXrefNameAndPath + '\n')

            if changed == True:
                logReport = (logReport + '\n')
                if simulateFolderOnOff == False:
                    c4d.documents.SaveDocument(doc, fixFile, c4d.SAVEDOCUMENTFLAGS_0, c4d.FORMAT_C4DEXPORT)
                if simulateFolderOnOff == True:
                    theFileName = self.get_name(fixFile)
                    simFolder_name = (simulateFolder + '/' + theFileName)
                    c4d.documents.SaveDocument(doc, simFolder_name, c4d.SAVEDOCUMENTFLAGS_0, c4d.FORMAT_C4DEXPORT)

            changed = False
            c4d.documents.KillDocument(doc)

        return logReport